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How The F*#% Do I Model This? - Reply for help with specific shapes - (Post attempt before asking)

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  • FrankPolygon
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    FrankPolygon sublime tool
    @CodeferBlue You're welcome.

    Like Sacboi mentioned: evaluating the overall form before blocking out the shapes will help inform which topology layouts, modeling tools and order of operations will be most effective.

    Looking at the silhouette of this object, the negative space above the grip is a major feature and since this shape interacts with the shape of the stock and the grip it should be part of the basic block out. Leaving out major features and trying to add them in later can cause issues because it often requires significantly reworking the surrounding geometry to make everything fit and flow together.


    The object's surface can be divided into two basic categories: flat areas (lighter overlay) and rounded transitional areas (darker overlay). Comparing the overall shape of the silhouette, surface types, shape profiles and shape transitions will help inform how the topology flow should be structured.



    The topology layout should support the major features by providing an organized path for the shape transitions to flow around the shapes. Matching the segments of the adjacent shapes and providing enough space for the support loops and shape transitions will require some adjustments to the mesh but it's much easier to work through this now than it would be to try and graft in additional geometry later.

    This example shows how the topology flows around the edges of the silhouette, major features and transitional shapes. Adding support loops (highlighted) will prevent any stray topology on the flat surfaces from effecting the smoothing of the rounded shapes and can also be used to sharpen the edge of the shape transition. Softer shapes that have matching geometry segments may not require the use of support loops.


    The important thing is to generate accurate geometry and consistent topology flow in the areas that matter. In most cases there's minimal benefit to carrying excess edge loops across flat areas or spending a lot of time trying to maintain a perfect grid topology across the entire mesh. If the major shapes are accurate and the rest of the mesh subdivides cleanly without causing any major smoothing artifacts then it's passable.
  • CodeferBlue
  • kuronekoshiii
    What is the proper way to achieve this model without error? 

    This is how I always ended up.




  • FrankPolygon
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    FrankPolygon sublime tool
    @kuronekoshiii The sharper corners will need support loops to prevent the shapes from collapsing and the smoothing artifacts across the rest of the shape can be resolved by removing the excess geometry and edge loops that cross over into the curved shapes. Flat surfaces are largely uneffected by triangles and n-gons so they can be a good place to end the extra edge loops.

    Try simplifying the starting geometry, matching the segment counts of adjacent shapes whenever practical and adding support loops around major shape transitions with a bevel / chamfer operation or modifier. Here's an example of what this could look like:


  • kuronekoshiii
  • G0056
    Hi, I'm trying to model the receiver of a shotgun and I'm having some problems:


    this little bumps are tricky to model, and make them look good with the superior part of the model.

    First I tried modeling the superior part(I was having some problems with the plane shape, but I achieved to make it. But before that, I don't know how to create that shape in the lateral zone. I tried using booleans but it looks bad when connecting with the superior zone.



    How do you think that could be the best way to approach this model?
  • dolya
    G0056 said:
    Hi, I'm trying to model the receiver of a shotgun and I'm having some problems:


    this little bumps are tricky to model, and make them look good with the superior part of the model.

    First I tried modeling the superior part(I was having some problems with the plane shape, but I achieved to make it. But before that, I don't know how to create that shape in the lateral zone. I tried using booleans but it looks bad when connecting with the superior zone.



    How do you think that could be the best way to approach this model?
    https://www.pinterest.com/pin/352688214571164044/
    take this, i hope this help u
  • Daf57
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    Daf57 polycounter lvl 5
    Hi all,

    Using Blender: sorry don't have an attempt, I have no idea how to achieve this - coming from Max to Blender I'm at a loss substituting curves for splines. I did try manually extruding verts but it wasn't pretty. I'm hoping there is a better solution - I'd like to get a tight weave and windings (2nd photo).
    Any suggestions on getting the wire loop and braid like the first image?



    And on the other end of the string ...
    I'm finding the twist and screw modifier, and the lack of a helix function, somewhat challenging. :(
    Thanks for any help with this!
    Daf
  • birb
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    birb polygon
    Daf57 said:
    Hi all,

    Using Blender: sorry don't have an attempt, I have no idea how to achieve this - coming from Max to Blender I'm at a loss substituting curves for splines. I did try manually extruding verts but it wasn't pretty. I'm hoping there is a better solution - I'd like to get a tight weave and windings (2nd photo).
    Any suggestions on getting the wire loop and braid like the first image?

    (snip)

    And on the other end of the string ...
    I'm finding the twist and screw modifier, and the lack of a helix function, somewhat challenging. :(

    (snip)
    You want the Screw modifier.

    Here's an example using only vertices with Skin & Subsurf for thickness + Screw for twisting. You'll need to do a quick reading on Skin in case you're going this route but are unfamiliar with it.



  • FrankPolygon
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    FrankPolygon sublime tool
    @G0056 There's a few different ways to approach modeling this shape but with most complex shape intersections it's best practice to block out the major forms and match the segment counts of the adjacent shapes so the intersecting geometry matches the base geometry reasonably well. How accurate this segment matching needs to be will depend entirely on the overall goals for the project.

    Here's an example that shows how matching the segments of the rounded fillet on the side to the segments of the round over on the top allows the support loop to flow around the shapes without causing any major smoothing artifacts.



    If the overall shape accuracy is a concern then it's important to block out all of the major forms before adding support loops or surface details. It's also probably worth finding some additional reference images that have less lens distortion and using those as a guide to blocking out the overall forms.

    Boolean operations are a great option for building up the block out in stages (similar to how the actual object was produced) and can make it easier to adjust the individual mesh elements when matching the segment counts of adjacent shapes. Adding the support loops to the final cage mesh with a bevel / chamfer modifier can make it easier to add details or adjust the edge width during baking tests.

    Provided the geometry subdivides cleanly, without causing any smoothing artifacts and provided there isn't a valid technical restraint then it's also acceptable to use triangles and n-gons in a subdivision cage mesh.

    Here's an example of this process with triangle and n-gon topology.


    To recap:
    • Block out the major forms before adding support loops and details.
    • Match the segments of intersecting geometry whenever it's reasonable to do so.
    • Use modifiers to automate tasks and enhance edit ability whenever it makes sense.
  • Daf57
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    Daf57 polycounter lvl 5
    @birb - thanks, I'll give that a go and see how I do. Thanks again.
  • tatertots
    Hi everyone, 

    I've spent quite a bit of time getting the following form correct:
     

    I'm talking specifically about the black bolt in the middle. It seems like a normal round bolt but with a number of cuts made out and a slanting edge upwards, which ends in a curve. After trying many different approaches, this is the best I've managed to do so far:



    The idea here was to make sure the supporting geometry for the vertical edge loops were there from the start. So they could be edge slided closer to the cut-out to make those edges sharp, without having the pinching effect they create seep through to the top of the screw. The result is the best I've managed so far. Some remarks:
    • The surfaces at the top going from the straight cut out the rounded shape upwards are non-planar unfortunately. This might be the reason for the weird shading in the corners, below
    • The corner part right now is a quad, I've tried it with a triangle before but that created a 5-pole in the corner which lead to a lot of pinching from the corner outwards (on the non-cutout circular shape in the middle). (See blue arrows)




    It doesn't look to bad. And it its a very small part in the total render. But I would really like to know how to solve a problem like this "The Right Way" (TM). :)

    Anybody could point me in the right direction here please?
    Thanks in advance!

    -Tom
  • FrankPolygon
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    FrankPolygon sublime tool
    @tatertots In general: it's best practice to maintain the concentricity and consistent spacing of the edge segments that make up the walls of cylindrical shapes. Moving the edge segments too far out of position will cause the subdivision smoothing to either pinch or pull the mesh around the shape intersection and this can cause significant smoothing artifacts.

    There's best practices for how to approach the topology and modeling but in the end what's right for the project depends entirely on what the goals are. Evaluate how the model will be used, how accurate the shape needs to be, how much time can be spent, what tools are available, etc. and use those parameters to decide which way to approach the modeling and topology layout.

    It all comes down to what's an acceptable trade-off between time and accuracy. If it's a small part that will have a lot of grime or high frequency normal details and the smoothing artifacts can be contained in a small area then it's probably not worth spending a lot of time on trying to get a near perfect result.

    As for what's causing the smoothing artifacts: working off of the existing edge segments of cylindrical shapes will generally go in three directions:
    • Increasing the segment count to generate support geometry. (Not shown)
    • Placing support loops on the flat side of the shape intersection. (First row)
    • Placing support loops on both sides of the shape intersection. (Second row)

    In general, increasing the segment count does increase the accuracy of the shape but it's important to balance shape accuracy with working efficiency. Throwing an excessive amount of geometry at a topology problem generally results in an overly dense cage mesh that's harder to work with and this will reduce overall efficiency. Instead the goal should be to use the absolute minimum amount of geometry required to accurately hold the shapes and provide a smooth transition between surfaces.

    Working off the existing geometry can be be appealing because it's the path of least resistance. This is viable for smaller, less important parts but it can often lead to significant issues with shape accuracy and smoothing artifacts. Slicing up primitive shapes and placing the support loops on the flat side of the shape intersections can be a quick way to generate complex forms but it tends to produce rounded shape transitions that generate noticeable smoothing artifacts when the edge width of the support loops is reduced in an attempt to sharpen up the transition areas. Following this logic the next step is to add support loops on both sides of the shape transitions. Though this can work for some shapes it generally produces sharp pinching artifacts near the corners and also tends to deform the curvature of adjacent surfaces.

    The first two examples below show this approach and although it's definitely viable when speed is more important than accuracy the prominence of the smoothing artifacts will be a major drawback. Instead (as shown in the third example) treating the existing geometry as the support loops and adding or subtracting additional geometry between the existing edges is a much better alternative.



    The example below shows how routing the edge flow around the shape intersection and using the existing geometry as support loops produces a simple mesh that subdivides cleanly. Increasing the segment count of the larger cylinder shape increases the overall shape accuracy but it also increases the mesh complexity. Maintaining the flow of the existing geometry while also using it to support the intersecting geometry will tend to reduce the amount of geometry needed and make the mesh easier to work with. When deciding how much geometry to use the size and prominence of the shape will be a major factor. Try to balance shape accuracy with editability and efficiency.



    Subdivision modeling is an established discipline so when it comes to solving modeling and topology challenges it's important to research, test and evaluate existing strategies. A couple of post above there's a detailed discussion about a similar shape transition and a couple of pages back there's several discussions about adding or subtracting shapes from cylinders by using existing geometry as support loops. With practice it will become easier to identify which strategies will work best for a given situation.

    To recap:
    Try to maintain the curvature and segment spacing of the cylinder walls when adding shape intersections.
    Use the existing geometry as support loops for shape intersections.
    Research, test and evaluate different modeling and topology strategies.
  • tatertots
    Hey Frank, thanks for the extensive answer. I'm pretty new to modelling and I have to admit that after reading the answer 5 times or so, I still don't quite understand everything. :)

    While I have managed to reconstruct something that leads to similar results, it feels like a trial-and-error approach to get there. I have difficulty interpreting the screenshots you posted. You always post a sequence of three images. I understand the last version is the subdivided/smoothed version. However the step between the first and the second image is unclear. In the images you posted the first one of each series contains a pretty big ngon, which does pretty bad in subdivision. So I assume you start of with a simple version with ngons and then flesh out the geometry in step 2 and have the mesh in that step show the deformation of the subdivision modifier.

    Getting from step 1 to step 2 however is a difficult process though. I don't quite get the steps to do this in a straightforward way where I understand why each thing is happening. It's probably a bit much to explain in a single post.
    I found this resource here: http://wiki.polycount.com/wiki/Subdivision_Surface_Modeling

    I'll look at the video's and examples in the above link. Do you happen to have any other resources to recommend for the theory behind topology when subdivision modelling?


    I've gone a few more times through the process, and made some screenshots of the different steps I took and the reasoning between things. If you could look over it and correct me where I'm wrong? :)

    From top-bottom, left-right:
    1. Add edge loop where cut-out needs to be. Make it the right shape
    2. Remove all faces, add edges that make the flat area's and fill with ngons
    3. The supporting lines for this shape will be the vertical lines already available. So in order to make the cut-out without altering the supporting lines, I've inset the n-gons (and tweaked a bit). This creates a face loop loop around the detail which can be used to help sharpen the detail.
    4. Remove top ngon and add 3 edge-loops in the middle. Creating 4 faces in the middle
    5. In red I've marked a pole (3-pole), though I missed the pole next to the blue arrows (5-pole). The combination of these two poles bend the face-loops in the right directions. They cause the blue loop to circle the inner side of the detail, and the black loop to circle back up.
      This is also the reason we only need 4 faces (3 edge-loops) in the middle, because there's only 4 faces (purple lines) that run top to bottom.
    6. Result is all quads
    7. Adding two extra horizontal edge loops to sharpen up the detail at the top of the curve, and the flat bend in the center.
    8. Smooth subdividing. :)



    I hope with the logic above - if correct - that it'll help create a mental model on good topology and how to reason about it. I think the next time I run into a tricky situation like this (though the result seems so eas
  • Yogifi
    No questions, just wanted to thank you all who are answering questions and giving out advice. I've got so much to go through!

    And @FrankPolygon if you decide to put out a book I'd snap that up in a heartbeat, just picked up all your pdf tutorials today and will go through them tonight.

    Thanks for all the guidance everyone.

  • tatertots
    Hi Frank,

    Thank you so much for this very detailed explanation. This was very clear. I've tried and tested all the different approaches you described and this has given me a whole new view on how to use the bevel/chamfer tools and the inset tool. Insetting n-gons to create edge loops around the details you wish. Using the bevel tool to sharpen up details on both sides of loops. Really great. And less of a fear of "the n-gon". Also, dissolving the edges in the middle is much faster than whatever I was doing... I deleted the faces and then manually started connecting the edges and faces again to make the flat. :P 
    Also the workflow(?) that just starts with the ngrons and then creates more agreeable geometry from that starting point will be helpful in many more cases I believe.

    This is absolutely super valuable help, so thank you for taking time out of your day and helping out less experienced (=total noobie in my case) people. :)

    Of the all the approaches, the third approach with the boolean suited me least of all. I found it very difficult to get the boolean well positioned and found the manual approach to be faster in my case and more accurate. 

    And thanks to Yogifi for mentioning the pdf tutorials, got curious and found them. I'll buy them as well. Any good information on topology and workflow is very helpful right now. I'll also be looking to some of the older pages of this thread. Around 150 the images still mostly seem to work. Though the issue is often very similar where a subdivided mesh is shown (optimal display) and there's no clear idea of what the underlying topology actually looks like.

    For instance, the first picture in your previous post, showing the 3 different cylinders. I have no clue how the topolgy of those meshes relates to the methods and images with the descriptions of the 3 methods later in your post. It is hard to find the resemblance.

    Again, thank you so much for taking your time to answer these questions.

    EDIT:
    Quick additional question. Is there any particular order you would recommend for your 4 pdf's?
  • Yogifi

    I was planning on going through the weekly hard surface modeling challenge from 2014 (though I'm no where near prepared and instead decided to first go through all of Frank's detailed posts here). What you talk about with N-Gons and bevels to create the topology and join them up, I'm getting a good understand of myself just now after following this from a few pages back:

    Outside of specific project requirements, stock 3D certification programs and technical edge cases, there really isn't anything wrong with using triangles and n-gons in subdivision modeling. Flat surfaces are arguably the least effected by messy topology. As long as the corners are supported and the surfaces are co-planar then it should subdivide without causing any major problems. If a mesh is easy to edit and subdivides cleanly, without any major smoothing errors, then it's passable. There's a point where done is better than perfect.

    As an example: here's four subdivision previews (left column) and four topology strategies (right column) can anyone spot the subtle differences and match up which subdivision preview belongs to which mesh?



    The four topology samples (right column) are:
    1. Triangles and quads.
    2. N-gons, triangles and quads.
    3. Quads only (manual cleanup)
    4. Quads only (tool generated)

    The matching subdivision previews are directly across from the mesh samples.

    For most high poly baking models, what happens on the flat areas between the edge loops doesn't make much difference. As long as the shape intersections and the support loops are properly structured the flat areas will remain flat. They generally subdivide and bake without causing any major issues.

    There are edge cases like highly reflective surfaces where the quality of the mesh does effect some things but whether or not this is relevant for a project is something that can be validated with some test bakes.

    The n-gon mesh is easier to edit but there are some cases where curves need the stress from triangles to help pull the edge loops into shape.

    Manually cleaning up a mesh to make it all quads is a major pain and often a waste of time. Avoid throwing more work into bad geometry. If it's broken enough that it needs a lot of manual cleanup then it's probably worth rebuilding correctly.

    Take the time to plan out the shapes and match the segment counts between adjacent shapes. Plan out the edge flow so edge loops can be added without effecting critical shapes.

    Here's an example of how planning out the edge flow and working through the shapes will result in all quads with minimal cleanup. The segment count is a little higher than I would generally recommend for a game model of this scale but the assumption is that the corners on the USB ports need to be curved. This could have been done using a wider support loop on the corners but leaving it in shows how to deal with similar shapes that require more geometry.

    Start out with the basic shapes and define a clear path for the support loops to run out on. Match segment counts to minimize the amount of geometry required to support the shape. Rely on tools for creating basic geometry, curves and edge loops whenever possible.


    The support loops around the Micro USB port are added with a chamfer operation and run out between the two USB ports. The support loops inside the USB port are added with a loop cut and run out to the sides of the case and around the Micro USB port topology.



    Use a chamfer operation to add the support loops around the face of the USB port. Adjust the segment count on the circular case geometry and bridge the edge loops so all of the segments are connected. This side is now complete. The other side will have the same number of segments.


    Use the same segment count for the opposite side of the case and the button cut out. There's a support loop that holds the shape for the outside of the case and it eats up one segment of the button so an edge loop needs to be added between the case and the button to equalize the segment count. Additional support loops could be added to the right side of the button if necessary. Bridge the faces to close the geometry. The basic shape is now complete.


    Add additional support loops around the button and outside of the case. Move the center loops back to set the button depth and the seam depth between the case and face plate. Extrude the rest of the shape out to form the rest of the case. All quads and no manual cleanup work to remove triangles or n-gons. How much geometry is required will depend on the desired shape accuracy.


    Subdivision modeling is about planning out the edge flow and shape intersections while choosing the right trade-offs between efficiency and shape accuracy. If there's no hard requirement for all quads then use the minimum amount of geometry required to hold each shape. Triangles and n-gons that aren't causing smoothing problems are fine. In most cases (if they aren't causing smoothing errors) it's not worth the time to edit them out.

    Here's a comparison of two extremes: a mesh that leverages a lot of n-gons and a mesh that has been made all quads for compliance. The n-gon strategy is easy to work with but may not pass some strict QA / QC processes for stock 3D. The all quads compliance strategy hits this metric but the over optimized edge flow makes it difficult to add or remove loops. The geometry is locked in.

    What's right depends on the project and part of the process is balancing technical demands with the art process and time management. A product visualization model is going to have different requirements than a background prop for a mobile game. Narrowing down the scope of the project will help determine which strategies will work best.


    If a project genuinely requires all quad geometry: Take the time to plan the edge flow and block out the shapes ahead of time. Match each shape's segment count with surrounding geometry and run out edge loops where they won't disturb adjacent shapes.

    The mesh you already have shows a good compromise between efficiency and accuracy. There's only a couple spots that could cause problems with subdivision and even then it might not be a problem if the smoothing errors aren't visible when baked out and textured.

    Add the rest of the support loops and subdivide the mesh to see if there are any major smoothing problems. If the mesh looks good with subdivision then it's fine.


    I was always at a fork between should I be modeling this all quads, or follow what the youtubers are doing with booleans, bevels and creases - especially as I'm just starting out. I guess I still am a bit unsure but I will keep the advice from above in mind. Flat surfaces should be okay...I'll see about the curves.

    He doesn't provide a complete step-by-step video but I find I learn better when I have to overcome challenges myself and really studying the info to understand what's going on though it does take longer, especially when trying to figure out why he's done it that way.
    With the above example I was also having difficulty projecting the shapes onto the n-gon to have the edges connect where I wanted them to, but after some experimenting I found that when adding the loops for the connections, snapping to the vertex of the shape helps a lot.

    Anyway, I prepared the images of the first week from the 2014 challenge when a lot of the images have gone offline, but you can use archive.org and not always but quite often it will have a copy of the images - the linked ones anyway. Good tool to know about.

    - I can't answer your question on the best order to go through them as just following along with the above took me a while.

    Another great resource is Arrimus 3D's youtube playlist called 3ds max (I'm using blender and it's mostly quite easy to follow along). I'd start with the first 4 topology videos and skip along that playlist until he talks more about topology. He shows a really cool thought process to getting a circular object to blend smoothly into a square one in the second topology video. It's a very...very...very long playlist!

    _

    His request playlist is also awesome.

    At this rate I'm not going to get to the fun stuff like sculpting till next year :)

  • guitarguy00
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    guitarguy00 polycounter lvl 2





    Hey Frank, could you please tell me how you do the automatic chamfer in model number 3(middle left) here? Is it as simple as selecting to 2 edges in model 2(top right) and hitting the chamfer function in Blender(I'm assuming that is what you are using) and messing around with the edge count and falloff options?  Thanks in advance!
  • FrankPolygon
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    FrankPolygon sublime tool
    @Yogifi Thank you.

    @tatertots Thank you for taking the time to follow up your initial question with a detailed explanation of what you tried and what you were looking to improve. Glad you found the posts helpful.

    Cylinder intersections is a good place to start and from there the v block project covers three different approaches and the key project has a lot of cylinder intersections. The 123 block project relies heavily on Booleans and modifiers so it's probably best to leave that for last.

    In most cases the underlying geometry and topology layout is largely identical to what's shown with an optimized subdivision preview. This can often be useful because it shows how the subdivision smoothing is deforming the underlying topology but on the other hand it can also hide some subtle nuances. The feedback on the usefulness of seeing the different steps Vs just seeing the starting and final topology is worth noting. Something I'll keep in mind.

    A lot of artist have contributed to this thread over the years and it's a great resource. It's a shame that some of the earlier images have been lost but the pages from the last couple of years still have a lot of information. Lots of answers to commonly asked questions there.

    @guitarguy00
    You are correct: select the two outside edges and use either edge weights and a modifier or the manual tool to develop the round over along the outside of the shape profile. Working through the model in stages and relying on tools like bevel / chamfer to add these kind of details helps keep everything accurate, easy and simple. If the geometry needs support loops then they can be added by using a wider square chamfer operation before adding the round over or by using an inset operation on the flat area after the round over is added along the edges.
  • Yogifi
    I've still got to get through the guides, progress is not going anywhere near as fast as I thought. But I was looking at Arrimus's new video on boolean and bevels with different techniques (I'm doing the quads method) ...and  can't get creases and bevels to work nicely together so I'm just doing the bevels manually and leaving creases for now ..... but is this pinching supposed to happen or can this be improved:



    Subdivided on the right.

    Sorry if it's already been covered I was hoping for quick thoughts from experienced folks on the quads that look like triangles at the corners from the bevel. They clear up with subd but is the "low poly" supposed to look like that?

    Those triangular creases happen even if I don't join them up on the unsubdivided model:



    But if I don't join them up, when I subdivide I get this:


    I know subd doesn't really like n-gons (though I remember a video from Josh Gambell on youtube saying he could get it to work with n-gons but I forgot how...and I'd rather focus on the correct quad topology for now.

    Basically, is the low poly always going to be a mess? Until you get to the baking stage? (I haven't read into baking yet) and is this the correct topology? I tried inserting another loop in between the support loops of the bevel but it didn't really do anything.

    I feel like it isn't the correct topo. In fact, if I zoom in a lot, I can see some distortions even on the subd model. But then how are you supposed to add the bevels to a surface without the vertices to support them cleanly? I needed more dense topo? How come the youtubers can just bevel it with ngons even on curves and it looks right... man I don't know anything lol - other than about 100 custom hotkeys. I might have spent too long on the hotkeys and not enough on topology - I'm using one of those mini keyboards for ergonomics...thinking ahead for a tablet too but it means half the keys are with the Fn button!

  • Yogifi
    Damn... does this forum delete posts when you make too many edits? Keeps happening...

    I was trying to do the example that Arrimus did in today's video. He's talking about different strategies with booleans and I wanted to give the quad one a go.

    I think he uses creases but I couldn't get the subd to look right when I tried to crease and bevel so I just focussed on manual bevels but ran into some issues trying to connect up the bevel corners properly.

    Sub'd on the right, which looks much better but as shown below it's not perfect:




    If I don't connect those fan shaped quads in the corners, the sub'd gets messy with the n-gon:



    And for the non-subd, the pinching appears anyway:




    It looks okay when sub'd but not perfect:



    I feel like the topology isn't correct but I don't understand how else to connect it... should I have had a much denser mesh? It seemed quite reasonable:




    I was also wondering if the issues with the unsubdivided mesh were unavoidable? The non-subdivided model shades really really poorly. Is that what baking is for (I still need to start on reading about baking but focussing on the higher poly for now).

    I imagine if I ran extra loops up and across for the bevel of that one object it would shade better...but I thought we didn't need perfect quad topology to get nice shading. The youtubers seem to do with n-gons! And that surface is flat...and it's actually a quad not even a triangle with that fan shape... I feel like what I do in practice doesn't always match up with the advice I hear about quads vs ngons and triangles. And if I did run those loops round the object...the curve of the whole object would be affected! I know about set flow, but because the loops would be closer together...I guess that's why I had a more dense mesh to add in those details without distorting the shape too much...but is there a better way than just running extra loops all the way round for 2 vertices on a corner of that bevel?

    And I still need to go through a lot of material so I'm sorry if this has been covered before, I was hoping for some general advice but will keep trucking with the learning.

  • wirrexx
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    wirrexx interpolator
    Yogifi said:
    Damn... does this forum delete posts when you make too many edits? Keeps happening...

    I was trying to do the example that Arrimus did in today's video. He's talking about different strategies with booleans and I wanted to give the quad one a go.

    I think he uses creases but I couldn't get the subd to look right when I tried to crease and bevel so I just focussed on manual bevels but ran into some issues trying to connect up the bevel corners properly.

    Sub'd on the right, which looks much better but as shown below it's not perfect:




    If I don't connect those fan shaped quads in the corners, the sub'd gets messy with the n-gon:



    And for the non-subd, the pinching appears anyway:




    It looks okay when sub'd but not perfect:



    I feel like the topology isn't correct but I don't understand how else to connect it... should I have had a much denser mesh? It seemed quite reasonable:




    I was also wondering if the issues with the unsubdivided mesh were unavoidable? The non-subdivided model shades really really poorly - is that normal when it's curved and you bevel some corners on it? Is that what baking is for (I still need to start on reading about baking but focussing on the higher poly for now). I imagine if I ran extra loops up and across for the bevel of that one object it would shade better...but I thought we didn't need perfect quad topology to get nice shading. The youtubers seem to do with n-gons! And that surface is pretty flat...and it's actually a quad not even a triangle with that fan shape... I feel like what I do in practice doesn't always match up with the advice I hear about quads vs ngons and triangles. And if I did run those loops round the object...the curve of the whole object would be affected! I know about set flow, but because the loops would be closer together...I guess that's why I had a more dense mesh to add in those details without distorting the shape too much...but is there a better way than just running extra loops all the way round for 2 vertices on a corner of a bevel?

    And I still need to go through a lot of material so I'm sorry if this has been covered before, I was hoping for some general advice but will keep trucking with the learning.



  • FrankPolygon
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    FrankPolygon sublime tool
    @Yogifi There's a lot to unpack but the answer to most of these questions is: it often depends.

    There's a significant amount of overlap between poly modeling and subdivision modeling but they are still distinct processes that require slightly different approaches. What's "right" or "best" depends entirely on how a model will be used and what the limitations are. As an example: the requirements for a VFX model that will be used in a close up in a feature film will be quite different from the requirements for a background prop in a game. This is something that Arrimus mentions briefly at several points in his video.

    One of the major issues with trying to extrapolate some kind of perfect rule set from general technical overviews is that, without any context to guide why and when something should be done, it becomes very attractive to try and use relatively meaningless technical statistics as some kind of quality indicator. This is a primary factor in the perpetuation of some long standing misconceptions about certain geometry elements and modeling strategies.

    A good example of this is when an artist spends very little time on blocking out accurate shapes and instead jumps right into adding minor surface details and manually moving edge loops around for hours to maintain all quad geometry.

    This raises the question of where is the added value of the all quad topology if the model's shape is inaccurate and it took significantly longer to make? Subdivision modeling is a commodity and developing an efficient workflow will help an artist bring value to their skills set. Excessive manual topology rework and manually replicating work done by automated tools is something to avoid whenever possible.

    An all quad topology layout isn't inherently good and a topology layout with a lot of triangles and n-gons isn't inherently bad. It's much more important to judge a given model by specific project goals and evaluate how well the various geometry elements were used to optimize the return on the time spent.

    If all quad topology is a hard technical requirement then Boolean re-meshing workflows, including the one Arrimus covered in his video, can have a significant speed advantage over traditional subdivision workflows. (Though it's still worth mentioning that art fundamentals and an understanding of the basic concepts behind subdivision modeling are still an important part of this workflow.) Here's a couple of recent discussions with an artist who starts out with a Boolean re-meshing process and moves into a subdivision modeling workflow. This is a great example of how the overlapping modeling skills can transfer over.

    https://polycount.com/discussion/comment/2728288/#Comment_2728288
    Taking a broad view of things: the basic concepts, technical fundamentals and best practices for poly modeling and subdivision modeling are pretty cut and dry. This provides a solid foundation and is a great place to start learning about how things work. However, there comes a point where learning to be effective with subdivision modeling becomes less about how things are done and more about why things are done and when things are done. Building up this knowledge requires researching and practicing and can take some time to develop. It's all about picking up the tools and screwing up until the screw ups start to resemble completed work.

    With the subdivision models: a lot of the artifacts and smoothing issues are caused by mismatched curve segments (where there isn't enough adjacent geometry to support the shapes) and incorrect edge placement to control the subdivision smoothing behavior. Placing the edges on the outside segments of the corners does result in all quads but it also causes the center segment of the corner to collapse inwards. In general, when it's not possible to match the adjacent segments, it's better to have the center corner segment connected to the nearby geometry and pull the shape outwards.

    Flat surfaces are least likely to be effected by topology changes and are a good place to end extra edge loops. If smoothing artifacts are appearing on or around flat surfaces then then it's likely that either the geometry elements aren't completely coplanar or there's a missing support loop around the shape transitions. Sharp transitions between surfaces should generally be support by edge loops on both sides. It looks like there may be some spots where the geometry isn't fully supported and this could be causing some of the smoothing issues around the perimeter of the shapes.



    With the low poly shading and topology: it's important to use both the geometry and sharp edges to control the smooth shading behavior. Adjusting the geometry, triangulation and placing hard edges will help resolve some of the distortion in the low poly model. It's also important to optimize the low poly mesh by removing any geometry that doesn't add to the visible profiles of the major shapes.

    Here's an example of all smooth shaded, smooth shaded + hard edges and all smooth shaded + chamfer.



    Here's an example that compares two different topology layouts used to optimize the geometry for high poly (top) and low poly (bottom) models. The n-gons and center segment edge connections in the corners facilitated the use of edge weights to control a bevel / chamfer modifier to quickly and automatically add all of the supporting geometry without causing any major smoothing artifacts.



    There's a number of different strategies for creating low poly models. Starting with a fairly detailed base model that can be developed into both the subdivision cage mesh and the final low poly seems to be one of the more efficient approaches. It's also fine to keep the low poly topology organized with quads and n-gons while editing but it's also important to triangulate the mesh before exporting. Different applications can use different triangulation methodologies and without a set triangulation order there can be a triangulation mismatch between programs which can cause issues with baked normals.

    Here's an example of the source low poly and two different triangulation methods:



    A couple of great resources to learn more about normal baking are Joe Wilson's baking tutorial and Alec Moody's video about controlling shading behavior.


    The video about controlling shading behavior by Alec Moody:

    Three technical talk threads about normal baking:

    To recap:
    Start by learning the concepts and fundamentals then practice and evaluate the results rather than looking for absolute rules.
    Match the segments of intersecting geometry to the segments on the base geometry whenever it's reasonable to do so.
    Add intersecting geometry between the segments of the existing geometry and leave enough space for support loops on both sides.
  • Yogifi
    wirrexx said:

    <...quote...>


    Thank you very much for those lines, I keep forgetting about the 3 to 1 topology conversion.
    I did it try it though and I thought it would work but it didn't seem to fix the issue as much as it did just change the shape of the shading issue:


    And the extra loops around the corners made sharp lines corners for some reason on the ... flat surface (it was booleaned with a flat box!). I thought 3 lines around a corner was supposed to define it's shape well enough anyway ... or do you sometimes need more than 3 for a sharp corner?


    - I just saw your post Frank, thank you kindly. I will get some coffee and go over it.

  • Herbert
    Hi Guys, im trying to model this very simple object but turns out to be not as simple as it seems to me. 
    Basically i am interested in the parts where the cylinder and the sphere meet.

    initially i tried with boolean to union them together and mannually clean up the topology and that's where i had most headache

    first few attempts i tried to use normal UV spheres but it causes very noticeable pinching problem at the poles and the shading along the junction of two shapes is not ideal as well. 


    then i changed to rounded cube for the spherical part and it did remove the pinching problme at the poles but still cant figure out how to clean up the topoly where basically there are a lot of triangles and N-gons and causes me some shading problem at close distance. Thanks in advance! 

  • FrankPolygon
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    FrankPolygon sublime tool
    @Herbert You're on the right path and the mesh just needs some minor adjustments.

    When evaluating any potential smoothing artifacts it's worth considering the following factors:

    • How large is the object?
    • How closely will the player view the object?
    • How severe is the smoothing artifact?

    If the smoothing artifact is small and out of the way or if the smoothing artifact is very soft and will be covered by normal texture details then it may not make sense to spend a lot of effort trying to remove the smoothing artifact.

    Here's a comparison of a similar mesh with different matcaps. The glossy matcap with the environment texture and sharp highlights introduces a lot of extraneous surface reflections and some of these could be misinterpreted as potential smoothing artifacts.

    Changing the orientation of either the mesh or the lighting will change the highlight behavior so it's unlikely that this is caused by a smoothing artifact. Checking these results against a softer matcap with a broader highlight roll-off doesn't reveal any major smoothing artifacts so the S shaped highlight is likely caused by the transition from a simple curve to a compound curve where the cylinder and sphere intersect.

    Switching between a high gloss, sharp highlight and a medium gloss, soft highlight matcap can make smoothing artifacts easier to identify than using just a single matcap with a lot of extraneous details.



    There's several different ways to approach modeling this shape and which one makes sense will depend on whether or not the orientation of the larger sphere needs to be fixed to support other details. When it comes to the topology, the important thing is to match the segments where the shapes intersect and try to use the existing geometry of the sphere as a support loop for the intersecting shapes.

    If the sphere has to support additional geometry for other shape details and cannot be rotated then one approach would be to match the segments of the intersecting cylinder with the adjacent segments on the sphere. From there the existing geometry of the sphere acts as part of the support loop for the shape intersection and another support loop can be added to the cylinder to control the edge width of the shape transition. How dense the mesh needs to be will depend entirely on the size of the object and if there are any additional shape details.



    If the sphere doesn't have to support additional geometry or it can be rotated then another approach would be to simply rotate the sphere into a position where the intersecting cylinder lands inside of an existing ring segment. Existing topology can be used as support loops or additional support loops can be added to sharpen up the shape transitions.


    To recap:
    Switching between high gloss, sharp highlight and medium gloss, broad highlight matcaps can help make it easier to identify smoothing artifacts. Consider the size of the object, the severity of the smoothing artifacts and whether or not players will see them before investing additional time in perfecting a mesh.

    When modeling complex shape intersections:
    • Block out the shapes and plan out how the intersecting shape details will interact.
    • Line up the existing shape topology and match the adjacent segments whenever possible.
    • Try to intersect shape details between existing edges and use these existing edges as support loops.

  • tatertots
    @FrankPolygon

    Hey Frank, thanks for the extensive answer. I'm pretty new to modelling and I have to admit that after reading the answer 5 times or so, I still don't quite understand everything. :)

    While I have managed to reconstruct something that leads to similar results, it feels like a trial-and-error approach to get there. I have difficulty interpreting the screenshots you posted. You always post a sequence of three images. I understand the last version is the subdivided/smoothed version. However the step between the first and the second image is unclear. In the images you posted the first one of each series contains a pretty big ngon, which does pretty bad in subdivision. So I assume you start of with a simple version with ngons and then flesh out the geometry in step 2 and have the mesh in that step show the deformation of the subdivision modifier.

    Getting from step 1 to step 2 however is a difficult process though. I don't quite get the steps to do this in a straightforward way where I understand why each thing is happening. It's probably a bit much to explain in a single post.
    I found this resource here: http://wiki.polycount.com/wiki/Subdivision_Surface_Modeling

    I'll look at the video's and examples in the above link. Do you happen to have any other resources to recommend for the theory behind topology when subdivision modelling?

    ----------------

    I've gone a few more times through the process, and made some screenshots of the different steps I took and the reasoning between things. If you could look over it and correct me where I'm wrong? :)

    From top-bottom, left-right:
    1. Add edge loop where cut-out needs to be. Make it the right shape
    2. Remove all faces, add edges that make the flat area's and fill with ngons
    3. The supporting lines for this shape will be the vertical lines already available. So in order to make the cut-out without altering the supporting lines, I've inset the n-gons (and tweaked a bit). This creates a face loop loop around the detail which can be used to help sharpen the detail.
    4. Remove top ngon and add 3 edge-loops in the middle. Creating 4 faces in the middle
    5. In red I've marked a pole (3-pole), though I missed the pole next to the blue arrows (5-pole). The combination of these two poles bend the face-loops in the right directions. They cause the blue loop to circle the inner side of the detail, and the black loop to circle back up.
      This is also the reason we only need 4 faces (3 edge-loops) in the middle, because there's only 4 faces (purple lines) that run top to bottom.
    6. Result is all quads
    7. Adding two extra horizontal edge loops to sharpen up the detail at the top of the curve, and the flat bend in the center.
    8. Smooth subdividing. :)



    I hope with the logic above - if correct - that it'll help create a mental model on good topology and how to reason about it. I think the next time I run into a tricky situation like this (though the result seems so easy,... sigh) I'll be better equiped to deal with it.


  • Herbert
    @Herbert You're on the right path and the mesh just needs some minor adjustments.

    When evaluating any potential smoothing artifacts it's worth considering the following factors:

    • How large is the object?
    • How closely will the player view the object?
    • How severe is the smoothing artifact?

    If the smoothing artifact is small and out of the way or if the smoothing artifact is very soft and will be covered by normal texture details then it may not make sense to spend a lot of effort trying to remove the smoothing artifact.

    Here's a comparison of a similar mesh with different matcaps. The glossy matcap with the environment texture and sharp highlights introduces a lot of extraneous surface reflections and some of these could be misinterpreted as potential smoothing artifacts.

    Changing the orientation of either the mesh or the lighting will change the highlight behavior so it's unlikely that this is caused by a smoothing artifact. Checking these results against a softer matcap with a broader highlight roll-off doesn't reveal any major smoothing artifacts so the S shaped highlight is likely caused by the transition from a simple curve to a compound curve where the cylinder and sphere intersect.

    Switching between a high gloss, sharp highlight and a medium gloss, soft highlight matcap can make smoothing artifacts easier to identify than using just a single matcap with a lot of extraneous details.



    There's several different ways to approach modeling this shape and which one makes sense will depend on whether or not the orientation of the larger sphere needs to be fixed to support other details. When it comes to the topology, the important thing is to match the segments where the shapes intersect and try to use the existing geometry of the sphere as a support loop for the intersecting shapes.

    If the sphere has to support additional geometry for other shape details and cannot be rotated then one approach would be to match the segments of the intersecting cylinder with the adjacent segments on the sphere. From there the existing geometry of the sphere acts as part of the support loop for the shape intersection and another support loop can be added to the cylinder to control the edge width of the shape transition. How dense the mesh needs to be will depend entirely on the size of the object and if there are any additional shape details.



    If the sphere doesn't have to support additional geometry or it can be rotated then another approach would be to simply rotate the sphere into a position where the intersecting cylinder lands inside of an existing ring segment. Existing topology can be used as support loops or additional support loops can be added to sharpen up the shape transitions.


    To recap:
    Switching between high gloss, sharp highlight and medium gloss, broad highlight matcaps can help make it easier to identify smoothing artifacts. Consider the size of the object, the severity of the smoothing artifacts and whether or not players will see them before investing additional time in perfecting a mesh.

    When modeling complex shape intersections:
    • Block out the shapes and plan out how the intersecting shape details will interact.
    • Line up the existing shape topology and match the adjacent segments whenever possible.
    • Try to intersect shape details between existing edges and use these existing edges as support loops.


    Thank you so much! helped me out big time !! 
  • LilacGear
    Been working on this since the start of the lockdowns and I still can't figure it out. Trying to get a sharp edge cut into a cylinder


  • FrankPolygon
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    FrankPolygon sublime tool
    @LilacGear Welcome to polycount. A few post above there's a couple of discussions about adding or subtracting shapes from cylinders and curved surfaces and back on page 168 there's a little write up that covers working with a similar shapes on a curved surface. The principles covered in these discussions are the same that you'll want to apply to this shape.

    Here's a couple examples of how this could be done. Start off by blocking out the shapes and adjusting the number of segments on the cylinder so there's room for the support loops to end on the existing edge segments on the cylinder walls. From there it's a simple matter of adding the necessary support loops and continuing the geometry on the inside of the angled cut out.


    The corners can be sharpened by:
    • Sliding the edge segments closer to the center of the corners.
    • Adding additional support loops to the inside of the corner and merging them down to the outside vert in the corner's support loop.
    • Increasing the number of segments that make up the walls of the cylinder.

    No need to over complicate the mesh though. As long as the additional geometry remains relatively consistent and parallel to the face that makes up the edge segment there shouldn't be any major smoothing issues.

    Which approach and how much geometry is required will depend on what the model will be used for and how closely it will be viewed. There's more information on this topic in the last couple of pages so it's definitely worth skimming through and reading some of the other post here.


    To recap:
    • Search for existing solutions to similar problems and see if they can help resolve the issues with your shape.
    • Block out the major forms, adjust the segment counts of adjacent shapes so the existing geometry can be used as support loops.
    • Leave room for support loops that run across curved shapes by placing intersecting geometry between the edge segments.
  • wirrexx
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    wirrexx interpolator
    @FrankPolygon you're on fire lately, so many mini tut! Keep'em going my man! <3
  • DiamondDog
    Hey, iv been trying to improve my skill by modelling ar-15. I just cant do this boxy thing. I tried to just create it by brute force extruding but it doesnt feel right. How you would model it? Thanks in advance
  • FrankPolygon
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    FrankPolygon sublime tool
    @DiamondDog A couple of post above there's a few discussions about blocking out shapes, matching segments and creating base geometry that's suitable for subdivision or re-meshing. Even though these aren't the exact same shapes it's the same basic principles so it's something that takes a bit of work to figure out how to apply existing information to a specific shape. Definitely take some time to skim through the pages and look for similar shapes.

    That said: extruding off the existing grid is fine for basic shapes but with complex shape intersections (like that brass deflector) there's just too much going on for it to work well. Instead take the time to develop each shape independently, rotate them into position and merge them together. Blocking out the shapes, using Booleans to keep parts separate and saving incremental versions before making destructive edits will make the whole process  lot easier if anything goes wrong.

    Here's one way to approach the basic shape of the brass deflector: Start with the basic primitive shape, rotate it to match the reference, scale the peak down until it matches the reference, round over the top edges, round over the peak and make any final adjustments. Once all of the features match the references the shape can be added to the base model with a Boolean operation.



    Here's an example of how extruding shape profiles from existing geometry can be combined with Boolean operations to quickly and accurately block out complex shapes. Start with features that have known dimensions and use those to scale the rest of the mesh. One big advantage to creating shapes separately is any adjustments to those parts won't require re-building the entire mesh.



    To recap:
    Block out the basic shapes for scale and create more complex shapes independently before joining them to the base mesh.
    Research existing solutions for similar topology and make samples to see if they solve any issues that come up while modeling.
    Maintain some kind of incremental history of changes to the shapes in case a part needs rework.
  • sacboi
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    sacboi ngon master
    how do u start a new model i dont know how
    Hi there, welcome to Polycount and before posting it's always useful to familiarize oneself with certain guidelines/rules which by the way are listed on page 1 of this thread, not only for community cohesion but also invaluable for others to consider, then perhaps in turn share potential solutions or offer related advice.

    So just a few points to bear in mind, to enable us to assist you :

    • Please expand upon the 'subject' you're struggling with or give some context/background description?
    • Is there a possibility of posting an attempt/screenshot or indeed reference?
    • Level of experience?
    • Although in most cases not a necessity but nonetheless helpful, is your choice of 3D software?
    • And lastly, is the intent for practice or foreseeable Portfolio addition at a later date, etc?      
  • G0056
    I'm trying to model this shape:



    But when I add subdivision, it collapses and doesn't work like I want.




    I added support loops, but there is still that strange curve. How would be the correct topology that would get that shape without that kind of artifact?


  • FrankPolygon
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    FrankPolygon sublime tool
    @G0056 A few posts above there's a couple of discussions about how to use existing geometry as support loops and a few pages back there's a discussion about a similar shape. It's definitely worth taking some time to read through the posts and figure out a way to apply that information to the problem.

    The basic idea is to use the existing edge segments as support loops instead of extruding directly off of them. Depending on the size of the object and the severity of the artifact it may be necessary to increase the number of segments in the curve but there are ways to sharpen up the edges by sliding some of the support loops around. What's acceptable will depend on how closely the object will be viewed and how noticeable the smoothing artifacts are. Applying these concepts should resolve the smoothing artifact in that area.

    Here's an example of what that could look like:

  • MKO
    Hello there. I'm using cinema 4D for modeling and I'm kinda new to hard surface modeling. I have some pinching problems. I basically tried to model panels on my cylindrical object, but I'm not happy with my topology :/, I also don't have even edge distribution because of this detail and I don't want to add another loops around my cylindrical object because it would change the curvature. I really want to know the proper way of modeling these panels on curve surface while having pretty clean topology. I also didn't want to pick more segments on my cylinder because I'm also having some detail on the back of my object and modeling that spherical hole with lots of segments would be way harder for me.
    Thanks for your help guys!



  • FrankPolygon
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    FrankPolygon sublime tool
    @MKO It's likely the current smoothing artifacts are caused by a combination of factors: extruding directly off of the existing cylinder edge segments and the extra edge loops that run down into the corners.

    Before trying to resolve the issue there's a few things that are worth considering:

    • Will the object ever be viewed this closely?
    • Will the object ever be viewed from this angle?
    • Will the smoothing artifact be visible when the grainy plastic texture is applied?

    If the answers to any of these questions is no then it's probably not worth the time trying to resolve such a minor smoothing artifact. If any answer is yes then it's still worth considering how sharp the corners need to be. Depending on the texture size and view distance the benefit of using such sharp edges may be negligible at best. Using slightly softer edges tends to increase shape readability and can improve normal map performance when textures MIP down.

    Here's a comparison that shows how the visible difference in corner sharpness tends to decrease as distance increases. It's also worth noting that increasing the depth of the groove around the features increases the contrast. At longer distances this increased contrast around the shapes can have a larger impact on the perceived sharpness than actually sharpening the corners.



    A few post above (and a few pages back) there's some detailed discussions about how to minimize smoothing artifacts when adding shape intersections to curved surfaces. Definitely worth taking the time to read through that for a more detailed explanation.

    The basic idea is to use the existing edges as support loops by placing the intersecting shape between the edge segments that make up the cylinder wall. From there it should be as simple as adding a few basic support loops and reducing the amount of superfluous geometry that runs through the shapes. If the corners need to be sharpened up it's possible to add support loops on either side of the corners and just live with the resulting n-gon. A large part of subdivision modeling is about balancing accuracy and efficiency. It's just not worth chasing perfection on such a minor surface discrepancy unless the feature is going to be a focal point that fills the entire screen.

    Here's an example of what this could look like on a mesh with a similar segment count. It's certainly possible to do this with a lot less geometry but the basic principles are the same. All of the examples here are demonstrated on a flush rectangular feature with a groove around it (since it's harder to hide smoothing artifacts) but this will also work on a raised rectangular boss or a sunken rectangular pocket.



    To recap:
    • Research solutions to similar problems, make some test samples and see if that resolves the issue.
    • Take the time to plan out the topology and match the segments of adjacent shapes during the block out.
    • Use the existing edges of curved surfaces as support loops and place intersecting geometry between them.


  • LilacGear
    Thanks for the into. Currently reading through the backlog.
  • wirrexx
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    wirrexx interpolator
    To add too  @FrankPolygon post, a lot of you guys forget that you can use floaters, saves time and is less hassley.


    * Create your shape
    * Loops around the area you want to panel
    * Copy the face you want and "intrude", create support edges (depends on how hard you want them
    * turbosmooth x 2 and you have the results =)

    I made a softer version but you can easily go harder on the edges

  • MKO
    @FrankPolygon Thank you so much for this clean explanation and it really looks like it is way better to use these edges on my cylinder as supportive edges instead of extruding off them. This really helped me a lot. And also yea I will read similar posts to my problem here. <3
  • MKO
    @wirrexx I'm just not sure what do you mean by turbosmooth, I'm using cinema 4D.
  • wirrexx
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    wirrexx interpolator
    MKO said:
    @wirrexx I'm just not sure what do you mean by turbosmooth, I'm using cinema 4D.

    I think it's called smoothing deformer in Cinema Or Mesh smooth.
  • PleaseHelpMe
    I am trying to find a way to create the detailing on the bottom of the boot while keeping the smooth curve around the sole of the boot when subdivided and not get sharp planer looking edges on the curve. The way that I have the geo now gives me those hard edges, and I'm not sure how to add supporting edges to the extrusions without making that worse.
  • FrankPolygon
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    FrankPolygon sublime tool
    @PleaseHelpMe A few posts up there's a couple of discussions about adding shapes to curves. You'll want to read through those for a more detailed answer to why this is happening and how to resolve it but the basic idea is to maintain a relatively consistent spacing on the geometry that makes up the curved surface and use this existing geometry as support loops whenever possible.

    Adjusting the spacing of the segments along the curve will resolve most of the issues with the inconsistent smoothing behavior. Extruding directly off of the existing edge grid doesn't leave much room for additional support loops so it's going to be important to find a way to route them around the existing geometry. To make all of this work it may be necessary to increase the number of segments along the curved shape but it's worth creating a few test samples to figure out how dense the mesh needs to be.

    It's important to consider how closely the object will be viewed and what type of texture will be applied on top of it. Areas that aren't generally visible or have a lot of texture noise tend to be less important so the mesh doesn't have to be absolutely perfect. Try to find a balance between what looks good and what's going to be easy to work with.

    Here's a comparison of some mesh density samples with similar tread designs. Minimum viable appears two be two segments per lug and one segment per gap but wider lug spacing will likely require two segments as well. One to one segment spacing could work with a lot of manual modification or more obtuse modeling strategies but it's likely this approach won't be practical or economical for most projects.



    Here's a couple more examples that test the number of segments required to support more complex tread patterns with sharper edges. The results support the earlier conclusion that (for more complex patterns) each lug and gap requires at least two or more segments.



    Modeling strategy one must: only use basic modeling operations, be relatively accurate and be relatively fast and easy, with minimal adjustments or mesh editing..

    1. Establish the basic shape and tread profile while maintaining even segment spacing around the outer perimeter.
    2. Select and extrude the tread profile.
    3. Select and inset the gap between the lugs.
    4. Select and inset the top loop to create the perimeter support loops.
    5. Select and inset the side loops to create the height support loops.
    6. Adjust the support loops that ring the lug gap by scaling down slightly.

    Notes:
    The inset operation in step 3. extrudes all three faces the same distance along the normals and keeps the new geometry concentric with the cylinder. Alternate operations / tools (like solidify) may be required if the new geometry doesn't remain relatively concentric to the existing shapes. Step 6. is only necessary if the tools are unable to generate accurate shapes or if there's limited geometry as shown here in the first example.

    Here's an example of this process using two segments per lug and one segment per gap. This is fine for tread patterns with narrow gaps between the lugs but wider gaps will tend to require more segments.


    Here's an example of this process using two segments per lug and two segments per gap.



    Here's an example of this process using two segments per lug and three segments per gap. Maintaining an even width between edge segments only matters on the outer walls of the curved shape and the rest of the geometry can be adjusted to fit the tread pattern. Additional support loops can be cut into the bottom of the tread to support additional details.



    Modeling strategy two must: only use basic modeling operations and be fast and easy. Some cleanup is acceptable.

    1. Establish the basic shape and tread profile while maintaining even segment spacing around the outer perimeter.
    2. Select and extrude the tread profile.
    3. Select and chamfer / bevel the lugs.
    4. Select and dissolve the edge loop at the base of the lugs.
    5. Select the outer loop profile and scale down slightly.
    6. Chamfer / bevel the outer loop profile for a unique transition profile.
    7. Add additional surface details to the bottom of the treads.

    Notes:
    Steps 5.-7. are mostly optional. This strategy works on base meshes with lower segment counts but a base mesh that contains more segments will tend to produce a better result. On meshes that have large shapes with minimal supporting geometry this strategy will produce minor smoothing artifacts.

    In some cases, texture details like surface texture, rubber grain, cracks and dirt can render minor smoothing artifacts unnoticeable so this may be a good approach for smaller models or areas that won't be seen often.

    Here's an example of this process using two segments per lug and one segment per gap. Adding the secondary profile transitions can help by reducing the smoothing stress in the transition areas and can draw attention away from any minor smoothing issues that can appear on larger shapes that only use one or two segments.



    Modeling strategy three must: be fast.

    1. Establish the basic shape and tread profile while maintaining even segment spacing around the outer perimeter.
    2. Select and extrude the tread profile.
    3. Select and mark the edges that need support loops.
    4. Add a chamfer / bevel modifier.

    Notes: Modeling strategy number three is basically an automated version of strategy number two and relies on the accuracy of the modifier system and the density of the base mesh to reduce the severity of smoothing artifacts. The modifier system makes it easy to add to the base mesh or adjust the edge width at any time. This modeling strategy can work on meshes with lower segment counts but like the previous strategy it's more likely to cause smoothing issues.



    Modeling strategy four must: be relatively accurate and fast.

    1. Establish the basic shape of the outer lugs in a tillable pattern.
    2. Place a curved path around the areas where the outer lugs are.
    3. Use modifiers to copy the base geometry and deform it around the path.
    4. Grid fill supporting geometry in the center of the shape.
    5. Add additional surface shapes using floating geometry. (Can be merged down if necessary.)
    6. Cut in supporting geometry.

    Notes:
    This is an easy way to add complex tread patterns with a minimal amount of repetitive work. It does require a modifier tool set that supports copying and deforming geometry along paths. The tread pattern remains editable for much of the process and can be adjusted as needed.

    Here's what the tileable mesh tread looks like. The geometry is relatively even and all of the supporting loops match up. Any combination of tread pattern could be created and the deformation modifier will adjust the geometry to fit the shape outline.



    Here's what the tiled tread pattern looks like when it's made editable. The inner geometry is generated automatically with a grid fill operation. This is a very quick way to add a lot of repetitive details while maintaining shape accuracy. Floating geometry will work fine with most baking workflows but may not be the best choice for a sculpting workflow. These minor details could be merged into the main shape using an n-gon, triangulate, quadify approach or a bridge edge loops operation.



    There's definitely more than one way to model this so which approach makes the most sense depends on what the model will be used for and how accurate the shape needs to be. As long as the mesh subdivides cleanly and there aren't any major smoothing artifacts it should be passable.

    Part of subdivision modeling is balancing accuracy and efficiency so if the treads on the boots are a minor part of the character then it's probably not worth spending a whole lot of time on them. Obviously the flip side is if the model is used for product visualization or VFX then it's more important that all of these shapes are accurate.

    To recap:
    Maintain even segment spacing around the perimeter of curved shapes.
    Try to place intersecting shapes between the existing edges so the segments of the curve act as support loops. When this isn't possible try to have a place for the support loops to run around the shapes and out into an area where they won't effect the mesh smoothing.
    Determine whether or not an area of a model will be a focal point and dedicate an appropriate amount of resources.
    Look for existing information and figure out how to apply it to the problem at hand.
    Make samples of details that are causing problems and try different approaches to find the best solution.
  • PleaseHelpMe
    @FrankPolygon

    Thank you so much! I went back through some of the previous posts to see the discussions about adding shapes to curves and was able to get the results I wanted. The images helped a lot. I was able to go back in and space out the shapes on the sole of the shoe and redirects some of the edges to use as supporting edges for my geometry. Having the different strategies explained was also incredible, luckily there will not be any close-ups on the bottom of the shoe so I have some wiggle room. Seeing the different ways to handle it will definitely be useful in future projects. I'm still working on being smart with my topology and this was so helpful!
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