Substance Designer - Iray blocky shading

ABinhoF

Hey everyone,

I'm relatively new to Substance Designer/Painter, only started playing around with them recently - So I'm not sure if this is a bug, or if my settings are incorrect.

When I use Iray to render out the material on a mesh, I get these weird shading issues when using Environments which cast strong shadows. At the edges the shaded quads are very sharply defined. See below, on the handle and the bottom of the amphora. This happens in Substance Painter too. The image was rendered out in the Corsica HDRI Environment. I'm rendering on my GPU, a 2GB Nvidia GTX 760, and I have the latest Nvidia drivers.

Any idea what's going on? Thanks!

Froyok

Please start by attaching your log file : https://support.allegorithmic.com/documentation/display/SPDOC/Exporting+the+log+file

ABinhoF

Here's my log file! I tried switching to CPU rendering to see if it was a GPU problem, but got the same results.

Thanks for any help anyone can give me Should I move this to the bug thread?

Jerc

This is an inherent issue with raytrace/pathtrace rendering. Shadows are raytraced based on the geometry so with a strong light source like the sun, the geometry will cast a shadow on itself and the transition from light to shadow will be harsh
A common solution to this is to use shadowmaps, but Iray doesn't support it at the moment. 

I would simply advise to use a different environement map with a more diffuse lighting instead of a direct sunlight when dealing with low poly meshes.

ABinhoF

Ah, that's good to know. Changed to more diffuse lighting and am now getting better renders. Thanks Jerc!