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Re: Sketchbook: Frank Polygon

Subdivision sketches: miscellaneous cylinder topology.

These are a few examples of simple topology layouts that use segment matching to resolve shape intersections on curved surfaces. Only the key loop paths are shown, to simplify the presentation, and the n-gons could be resolved to all quad geometry using grid fill or manual loop cuts. Most of these shapes can be created with basic modeling operations. So this post is just a test for smaller pieces of content that don't require a lot of explanation. The next couple of posts will be the usual long form write-ups.

Angled cylindrical boss intersecting both flat and curved surfaces.

Toroidal section with intersecting cylinder.

Chamfered cylinder with rounded boss.

FrankPolygon

5 ·

Re: Sketchbook: Frank Polygon

Subdivision modeling: mesh density Vs loop structure on curved surfaces.

Sharpening corner details by adding support loops that interrupt the segment spacing of a curved surface will generally result in some kind of smoothing artifact. The example below demonstrates how adding the highlighted support loops to the existing edges of the cylinder produces an undesired faceting artifact.

Image: https://us.v-cdn.net/5021068/uploads/editor/d9/bay1f5y0hunq.jpg

Increasing the number of segments in the curved surface, until the desired level of edge sharpness is reached, is a common fix for this type of smoothing artifact. This approach to modeling tends to produce evenly spaced topology layouts that provide consistent results when subdivision smoothing is applied.

Though dense topology layouts tend to be predictable they can also be difficult to work with. Creating larger objects or sharper corners will often require adding a significant amount of geometry to the curve. Which can make it difficult to manage complex shape intersections that require a lot of manual clean up.

The example below shows just how much geometry is required to produce a relatively soft corner on a shape that doesn't take up much of the screen. Segment counts from left to right are 24, 48, 96. If the object needed to fill the screen and have fairly sharp edges it's quite possible that the density of the starting geometry would have to double or even triple to maintain the current level of corner sharpness.

Image: https://us.v-cdn.net/5021068/uploads/editor/o1/2c5l09aah14a.jpg

Adding support loops to the corners, that merge into the existing segments of the cylinder, is another option for resolving this type of smoothing artifact. This type of topology layout can be used to produce sharper corners with less starting geometry. When the support loops are generated by a bevel / chamfer modifier the width of the edge highlight can be adjusted any time before the modifier is applied.

Though this topology layout tends to be easier to work with and can be quite flexible when pared with support loops generated by modifiers, it does tend to have some minor artifacts that can be visible in the edge highlights around the outside corners. With sufficient starting geometry and minimal deformation of the underlying shapes these minor artifacts generally won't be visible at normal viewing distances.

The example below shows how this type of topology layout can be created with basic modeling operations. This modeling process starts by figuring out the minimum number of segments required to create all of the basic shapes. A loop is added to the middle of the cylinder and the shape of the loop is adjusted to match the concept references. Running a bevel / chamfer operation produces two loops that are a set distance apart then the depth and taper is added with an inset operation. Support loops are added around the highlighted edges with a bevel / chamfer modifier and subdivision is applied.

Bottom row shows the base mesh with the modifiers turned off, smoothing preview with the support loops added and shaded view of the subdivided model. The cylinder primitive used in this example has 48 segments.

Image: https://us.v-cdn.net/5021068/uploads/editor/6m/ybqfsybcda1v.jpg

Below is a comparison of both topology layouts with similar levels of edge sharpness. It's worth noting that the structured edge loops can produce a sharper edge highlight with significantly less geometry and minimal mesh complexity. The quality trade off being the slightly truncated edge highlight near the outside corners of the shape.

This same modeling and topology layout strategies can be applied to more complex shape intersections that are present on a lot of popular hard surface modeling exercises. With these kind of shapes it's often a good idea to start by trying to find the minimum number of segments required to hold the shapes. Assuming the radial features are symmetrical: if there's 8 tapered tabs and 8 tapered cut outs that's a minimum of 16 segments to capture the basic shapes.

Since these features are often curved along the shape of the underlying cylinder it makes sense to add a bit more geometry. Using two segments per feature and adding an additional segment for each of the tapered transitions brings the total minimum viable segment count up to 48 but using three segments per feature brought the segment count up to 64 and improved the smoothing results near the corners of the cut outs. From there the shapes themselves are pretty basic and can be create quickly with standard modeling operations.

Start by blocking out the basic shape of the cylinder. Add the loop cuts for the secondary surface features. Move a section of the new loops to create the basic outlines of the shapes and use inset to add depth and (edge taper) draft. Straighten out some of the edges and merge to remove the excess space between the shapes. Select the outline of the bottom lug and use inset again with the same settings to produce a consistent extrusion away from the main shape. Cut in another edge half way through the truncated cone at the bottom and use join through to create the basic angle of the shape. Dissolve the edge along the bottom of the shape to produce the tapered transition into the truncated cone. Setup the edge bevel weights and add a bevel modifier to generate the support loops.

Image: https://us.v-cdn.net/5021068/uploads/editor/ha/vdyoxwyxx7cq.jpg

This same topology layout strategy still works at lower density levels but after a certain point there just isn't enough starting geometry to hold the shapes and the smoothing artifacts around some of the loops become more apparent. For this shape a 48 segment starting primitive is about the limit before the artifacts become visually intrusive.

Image: https://us.v-cdn.net/5021068/uploads/editor/o8/ylsm0l13f529.jpg

There's some misconceptions about just how much geometry is actually required to hold radially tiling shapes and often the threshold is much lower than is expected. Increasing the geometry density is often a go to recommendation because it's simple to explain and is predictable. However it isn't always the most efficient way of doing things.

Well structured support loops that produce minimal shape distortion are generally going to be more efficient but the trade off is they sometimes produce very minor cut offs in the edge highlights. Another thing to consider is that: when trying to attach a single shape to a cylinder it's important to work between the segments but with radial details that are unbroken it's sometimes easier to just run the support loops around the continuous shapes.

In this case very few of the support loops actually displace or disrupt the vertical edges of the cylinder so it doesn't cause a smoothing issue. On this shape the reasons this works is because most of the support loops are perpendicular or diagonal to the existing edges that make up the wall of the cylinder so instead of displacing the geometry sideways it just moves it upwards which doesn't effect the underlying curvature.

Recap:

Increasing the density of the starting primitives does tend to increase the sharpness of surface features on a curved surface. However this increase in geometry does have diminishing returns and there's a steep fall off in editability as the mesh density increases.

Using well structured support loops that merge into the existing geometry can be used to create sharper surface features with less starting geometry but there are some tradeoffs in visual quality when minor artifacts appear near the outside corners.

Both approaches are viable so it really comes down to whether or not the tradeoffs are acceptable for a given project.

FrankPolygon

4 ·

Re: Brutal Knights - Game Project/Learning Experience

It's just more fun fighting skeletons when the explode!

Bolovorix

7 ·

Re: Natalia's Art corner

Hi Polycount! Here's my latest sculpt! :) More on https://www.artstation.com/artwork/4XxLKL & https://www.instagram.com/natalia_p_gutierrez/ if you're interested! Thank you!

Cersei_Lannister

4 ·

Re: Airbørn

killnpc

5 ·

Dragon hunters weapons

Finished up the props for the character.

There's also a lighting turnaround vid here https://www.artstation.com/artwork/QnVZJE (not sure if there's a way to embed videos on polycount so I just linked it.)

These shiny metallic props turned out to be trickier than expected. Its tough to make sure details and variation are subtle enough but also visible. I decided to put some extra time on them so I could have them as a separate piece on my portfolio, initially they were just going to be props with a character and I wasn't planning on making them nice enough to be a standalone piece. I think it turned out ok in the end.

Ottomotto

3 ·

Re: The Bi-Monthly Environment Art Challenge | July - August (79)

Hey :) Started on the plant container. My plan is to bake an atlas and then uv the lowpoly to it.

At first I modeled the tubes directly on the cylindrical glass + mirror and shrinkwrap modifier and bent other elements with simple deform modifiers.

Then I switched to UV mesh from cylinder and deformed the elements with it, seems more simple.

However I'm wondering if there is a way to quickly un and rebind multiple objects surface deform modifier after having modied their geometry?

Current wip

Fabi_G

6 ·

Re: Is there a way to instantly turn lowpoly model to rough highpoly model?

For UE use : do your best to generate decent-ish UVs (ideally by proactively marking seams on the pieces as you model them), and bake down the Blender bevel node (or the Modo/Max/Maya equivalent) to a normalmap.

Or, bake everything (with hard edges) as an Object Space normalmap, blur it ever so slightly, and convert it back to the desired tangent space. The downside of this is that the blurred edges will only appear as intended over continuous UVs but not at UV splits which will just show a small shading artefact (resulting of the blending of the island color with the background). Whereas if you use the bevel node they will all show up everywhere regardless.

Two benefits from there : no highpoly is ever involved, and you end up with a model with UVs ready for automatic texturing in SP or any other texturing tool.

Lastly, you could also simply model everything with the desired non-destructive bevels/chamfer modifier you mentioned yourself. That is by far the most simple and straightforward solution, so why not just do that ? And for the parts that glitch out like on your screenshot, then just don't use it there. Or stack the effect multiple times depending on the widths you need.

(BTW, sharing some test meshes would probably be a good idea too)

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Oh and : I can't help but notice that there aren't any screenshots showing your UE rendering experiments using these models. In practice there is actually no guarantee that you'll even need any these hypothetical edge processing effects on your models to achieve the high level goal you are after... Any conjecture on that is pretty much pointless until you actually test out your final rendering really.