Subdividing a cylinder surface causes weird render problems - help please!

Support Modeling
1

I’m having an issue with dense models. Basically the smoother the wireframe the more blocky the render gets, displaying strange facets. The easiest way to produce this problem is using the Subdivision Surface modifier in Simple mode but manually subdividing the mesh also works. The more subdivisions I set in the modifier, the more edges appear in render.
I have tried all the smoothing settings, shade smooth, auto smooth with all kinds of degree settings, loop cuts, edge splits, increased quality, tried the adaptive subdiv modifier, nothing works.

I really need a dense model because of fine microdisplacement via the shader.
I used this archvis model for example but I could replicate the problem with a simple standard cylinder so it is definitely not the model.

Could you please help me because it drives me nuts!
thanks!

dense%20model%20problem
dense%20model%20problem1659×1084 1.11 MB

2

Except that it is definitely the model. You’re adding divisions around plane changes, and creating more flat faces, leaving less room for averaging the normals. If you want smooth subdivisions, you need to preserve the curvature when subdividing. Crease all your hard edges and subdivide with Catmull-Clark.

3

When you use the subdivision modifier in “simple” mode, it just subdivides the surface without smoothing anything. So the result you get is expected.

4

OK great, thank you both!!
I spent hours looking for this simple piece of info without results but armed with this knowledge I resolved the problem. It still gives me some facets but I guess I’ll need to add some further edge loops.