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:
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!
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.
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.
@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.
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.
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.
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!
@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.
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:
Add edge loop where cut-out needs to be. Make it the right shape
Remove all faces, add edges that make the flat area's and fill with ngons
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.
Remove top ngon and add 3 edge-loops in the middle. Creating 4 faces in the middle
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.
Result is all quads
Adding two extra horizontal edge loops to sharpen up the detail at the top of the curve, and the flat bend in the center.
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 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.
@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.
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
@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.
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?
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?
@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.
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!
@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.
@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.
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.
@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..
Establish the basic shape and tread profile while maintaining even segment spacing around the outer perimeter.
Select and extrude the tread profile.
Select and inset the gap between the lugs.
Select and inset the top loop to create the perimeter support loops.
Select and inset the side loops to create the height support loops.
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.
Establish the basic shape and tread profile while maintaining even segment spacing around the outer perimeter.
Select and extrude the tread profile.
Select and chamfer / bevel the lugs.
Select and dissolve the edge loop at the base of the lugs.
Select the outer loop profile and scale down slightly.
Chamfer / bevel the outer loop profile for a unique transition profile.
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.
Establish the basic shape and tread profile while maintaining even segment spacing around the outer perimeter.
Select and extrude the tread profile.
Select and mark the edges that need support loops.
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.
Establish the basic shape of the outer lugs in a tillable pattern.
Place a curved path around the areas where the outer lugs are.
Use modifiers to copy the base geometry and deform it around the path.
Grid fill supporting geometry in the center of the shape.
Add additional surface shapes using floating geometry. (Can be merged down if necessary.)
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.
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!
Good day guys, what is the proper way to do this? I'm still a beginner and all I see in the tutorial is circle boolean and squares. but this, no tips on this. I want to learn the proper way.
@kuronekoshiii This shape is essentially an oblong through hole so the same principles apply: place the intersecting geometry between the existing edges of the cylinder wall, match the segment counts on both shapes and use the existing geometry as support loops. How much geometry needs to be used depends on how accurate the shapes needs to be.
There's several ways to approach modeling this but here's an example of what it could look like:
Arrange the intersecting shapes.
Match the segment counts on both shapes, using the existing edges on the cylinder wall as support loops.
Run the boolean subtraction and split the shape into eights and add a mirror modifier.
Merge down any stray vertices to the nearest adjacent vertex that's in line with the cylinder wall.
Add the support loops around the shape with a chamfer / bevel operation and merge dissolve any stray geometry.
Add the corner support loops.
(Optional) select the inside edge loop and add a bevel to soften the shape transition.
I am having significant trouble modeling this door, especially the corner, is there a different method I should employ when adding my edge loops
This problem can be easily fixed by just using a "Weighted Normals" modifier, or adjusting the normals bij hand in 3ds Max. It's a smoothing issue that is caused if you don't subdiv model and just bevel the edges. But it is also really easy to fix.
@sandrokaza There's a couple of detailed write-ups for similar shapes on the previous page of this thread. The basic idea is to use the existing geometry as support loops by placing the intersecting geometry between the existing edge segments on the cylinder walls.
There's more than one way to approach modeling this so the order of operations and mesh density can vary but here's an example of one approach:
Select the faces that outline the shape and inset to create a support loop.
Delete any unnecessary geometry.
Add additional support loops.
Solidify the shape and add additional support loops.
Here's an additional example that uses the same shapes and a similar extrusion process to create a pocket.
@kuronekoshiii It depends on what the rest of the shape looks like but one approach would be to add support loops above and below the shape transition then add a loop around the inside perimeter of the flat area. The corner topology is well supported and can be resolved with triangles or n-gons since any smoothing artifacts would be relatively minor.
Alternately: if the goal is to avoid manually editing support loops that are generated by a chamfer / bevel modifier then it's likely the underlying geometry will need to be adjusted or simplified to provide space for the support loops.
It all comes down to balancing accuracy and efficiency. Preserving sharp corner details sometimes requires manual adjustments and simplifying the mesh or adjusting the shapes so the chamfer / bevel modifier works correctly can require deviating slightly from the actual shapes.
Here's an example of what it looks like if each support loop is added independently.
It's also possible to add these support loops in a single chamfer / bevel operation and just clean up the mess in the corner. Here's an example of what that process looks like:
@sandrokaza There's a couple of detailed write-ups for similar shapes on the previous page of this thread. The basic idea is to use the existing geometry as support loops by placing the intersecting geometry between the existing edge segments on the cylinder walls.
There's more than one way to approach modeling this so the order of operations and mesh density can vary but here's an example of one approach:
Select the faces that outline the shape and inset to create a support loop.
Delete any unnecessary geometry.
Add additional support loops.
Solidify the shape and add additional support loops.
Here's an additional example that uses the same shapes and a similar extrusion process to create a pocket.
@kuronekoshiii It depends on what the rest of the shape looks like but one approach would be to add support loops above and below the shape transition then add a loop around the inside perimeter of the flat area. The corner topology is well supported and can be resolved with triangles or n-gons since any smoothing artifacts would be relatively minor.
Alternately: if the goal is to avoid manually editing support loops that are generated by a chamfer / bevel modifier then it's likely the underlying geometry will need to be adjusted or simplified to provide space for the support loops.
It all comes down to balancing accuracy and efficiency. Preserving sharp corner details sometimes requires manual adjustments and simplifying the mesh or adjusting the shapes so the chamfer / bevel modifier works correctly can require deviating slightly from the actual shapes.
Here's an example of what it looks like if each support loop is added independently.
It's also possible to add these support loops in a single chamfer / bevel operation and just clean up the mess in the corner. Here's an example of what that process looks like:
@sandrokaza There's a couple of detailed write-ups for similar shapes on the previous page of this thread. The basic idea is to use the existing geometry as support loops by placing the intersecting geometry between the existing edge segments on the cylinder walls.
There's more than one way to approach modeling this so the order of operations and mesh density can vary but here's an example of one approach:
Select the faces that outline the shape and inset to create a support loop.
Delete any unnecessary geometry.
Add additional support loops.
Solidify the shape and add additional support loops.
Here's an additional example that uses the same shapes and a similar extrusion process to create a pocket.
@kuronekoshiii It depends on what the rest of the shape looks like but one approach would be to add support loops above and below the shape transition then add a loop around the inside perimeter of the flat area. The corner topology is well supported and can be resolved with triangles or n-gons since any smoothing artifacts would be relatively minor.
Alternately: if the goal is to avoid manually editing support loops that are generated by a chamfer / bevel modifier then it's likely the underlying geometry will need to be adjusted or simplified to provide space for the support loops.
It all comes down to balancing accuracy and efficiency. Preserving sharp corner details sometimes requires manual adjustments and simplifying the mesh or adjusting the shapes so the chamfer / bevel modifier works correctly can require deviating slightly from the actual shapes.
Here's an example of what it looks like if each support loop is added independently.
It's also possible to add these support loops in a single chamfer / bevel operation and just clean up the mess in the corner. Here's an example of what that process looks like:
@Elphobos This thread is full of examples of subdivision modeling strategies so it's worth taking some time to skim through the pages and look at how other artists have created similar shapes. If there's an issue that's particularly difficult then post some images of the model in wire frame and subdivision preview mode. It's also important to explain what was attempted, what went wrong and what the desired result is.
It's generally considered best practice to start by blocking out the major shapes until there's enough geometry then move on to adding smaller details and support loops. Lot's of different modeling strategies but it's worth mentioning that mirroring and modifiers can speed up the process quite a bit. Here's an example of what this process could look like:
@G0056 It looks like you're using Blender so try changing the Outer Miter Pattern
from Sharp to Arc. There's also certain situations where adjacent
topology can interfere with bevel modifier and the only solution is to
adjust the topology elements in the base mesh until the modifier behaves
as expected.
This thread has a lot of information about adding support loops so it's probably worth taking some time to skim through and find some examples that fit what you're working on. Here's some direct links to a few recent discussions that are relevant to this question:
Frame topology comparison between subdivision modeling and re-meshing workflows:
Additionally, I'd also suggest researching 'floaters' (floating geometry) which in various situations, may be more beneficial aside from attempting too 'hard model' particularly fine surface details within confined regions of a contiguous mesh:
Good day, guys I'm just wondering how do you guys usually deal with this kind of corners, I already learned some of this from you guys about the support loops, but this time the support loop is creating a bevel like effects, I tried to move it to adjust the smooth but the pointy corner is having a problem when I do that since it is a part of its support.
@kuronekoshiii It's important to maintain a relatively consistent segment spacing along the walls of curved surfaces. Since the larger curved shape merges into a flat area (that's perpendicular to the curved surface) there's no real benefit to extending the edge loops off of the tab shape and into the wall of the curved surface.
Instead: block out the basic shapes then adjust the number of segments in the curved surface so the tab shape intersects between the existing vertical edges that make up the wall of the curved shape. This way the existing geometry (highlighted) becomes the support loops for the transition area around the shape intersections. From there the rest of the support loops can be added. Keep in mind that flat areas are largely impervious to topology changes and are a good place to end excess edge loops before they cross into other shapes.
With the proper topology the support loops can be adjusted as needed without adding segments to the curved shape. Here's a quick example of what this looks like:
This is the same principle discussed on the previous page and it will work for most shapes. It's deceptively simple and somewhat counter intuitive because it seems like it's a bit more work than connecting directly to the existing geometry.
The problem with working directly off the existing grid is there's either too much or too little room between the adjacent supporting geometry. This causes the geometry added by the subdivision smoothing to either bunch up or stretch out and that's what causes most smoothing artifacts. How much geometry is needed in a cage mesh depends on the shapes and the desired edge width but simplicity often has it's own virtues.
Hello, guys. I am working on this mesh and I can't really figure out how I can combine cylinder and the corner of a box smoothly like this one
Here is my work and found that I end up with wobbly line around the area where a cylinder meets a corner of the box.. any idea how to combine these two smoothly?
@jimdrawandmake A couple of posts above there's a discussion about preserving crisp edges and sharp corners when merging cylinders into other shapes. There's also a recent post about merging details into curved geometry and that links back to a previous discussion that may be useful for other parts of the shapes in the picture. Lots of good information about modeling strategies and topology layouts in this thread so it's worth the time to run back a few pages and skim through the posts for detailed write-ups of similar shapes.
It's generally considered best practice to block out all of the major shapes before modeling details and adding support loops. Starting with a block out is important because it's a way to preview how adjacent shape geometry interacts and make adjustments to things before investing a significant amount of time into the model. This makes it much easier to identify and correct topology issues before they become major time sinks.
With complex shape intersections it's important to use the existing geometry as support loops and to match the segments of intersecting curves whenever possible. It's also worth mentioning that the flat surfaces can be a good place to stop edge loops so they don't cross curved surfaces. Using a mirror modifier can also help reduce the amount of work that needs to be done. There's more detailed information linked above so here's a preview of what this process could look like:
Once the primary shapes are established then details and support loops can be added. This process can be partially or completely automated if bevel / chamfer modifiers are available. Some shapes may require adjustments to produce the desired results. The interior support loop for the sharp corners is on a flat surface so, provided the mesh subdivides without causing any major smoothing artifacts, it would be acceptable to resolve the topology in this area with triangles or n-gons.
The example at the end of the first row and the beginning of the second row are the same mesh and the models subdivides cleanly. How much additional geometry is required depends on whether the details are added as separate objects, floating geometry or part of a watertight mesh.
To recap:
Block out the major shapes before adding support loops and minor surface details.
Place intersecting geometry between the segments of curves to use the existing geometry as support loops.
Match the segments of intersecting curves to avoid generating smoothing artifacts.
@kuronekoshiii It's important to maintain a relatively consistent segment spacing along the walls of curved surfaces. Since the larger curved shape merges into a flat area (that's perpendicular to the curved surface) there's no real benefit to extending the edge loops off of the tab shape and into the wall of the curved surface.
Instead: block out the basic shapes then adjust the number of segments in the curved surface so the tab shape intersects between the existing vertical edges that make up the wall of the curved shape. This way the existing geometry (highlighted) becomes the support loops for the transition area around the shape intersections. From there the rest of the support loops can be added. Keep in mind that flat areas are largely impervious to topology changes and are a good place to end excess edge loops before they cross into other shapes.
With the proper topology the support loops can be adjusted as needed without adding segments to the curved shape. Here's a quick example of what this looks like:
This is the same principle discussed on the previous page and it will work for most shapes. It's deceptively simple and somewhat counter intuitive because it seems like it's a bit more work than connecting directly to the existing geometry.
The problem with working directly off the existing grid is there's either too much or too little room between the adjacent supporting geometry. This causes the geometry added by the subdivision smoothing to either bunch up or stretch out and that's what causes most smoothing artifacts. How much geometry is needed in a cage mesh depends on the shapes and the desired edge width but simplicity often has it's own virtues.
Thank you ngon master !! I guess I'm just overdoing things.
How to model the wire mesh part of this fan? In Maya, I made a plane with criss-crossed pattern and an object with the required shape and then projected the plane over it using either shrinkwrap deformer or sculpt deformer. I also tried Edit mesh >project curve on mesh. Then I use the result to convert edges to curves and then extrude the wires. However, it only looks good in the parts where the bending isn't that extreme. Near the edges where the bend goes almost 90 degrees, the pattern kinda looses shape and the holes become too big and stretched. Not at all like the real thing. If anyone has any advice, please do tell.
@FrankPolygon Thank you so much! I was really frustrated by it and now you made it look so easy that I feel a little bit more confident with it. I will definitely go over the previous posts in the thread, Cheers!
Replies
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!
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:
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.
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.
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?
Thanks for your help guys!
I think it's called smoothing deformer in Cinema Or Mesh smooth.
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.
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!
There's a forum about that too. If you are experiencing issues with your baking, check out https://polycount.com/discussion/107196/youre-making-me-hard-making-sense-of-hard-edges-uvs-normal-maps-and-vertex-counts#latest
This problem can be easily fixed by just using a "Weighted Normals" modifier, or adjusting the normals bij hand in 3ds Max. It's a smoothing issue that is caused if you don't subdiv model and just bevel the edges. But it is also really easy to fix.
without subdivide,
with subdivide,
I've been following some of your tutorials here, but this time it has a pointy corner and I don't know what approach am I suppose to do.
When I use bevel modifier + subD, I have that pinching (Bevel set in angle, it works fine except in this place)
How could I solve it?
Here is my work and found that I end up with wobbly line around the area where a cylinder meets a corner of the box.. any idea how to combine these two smoothly?