QuoteThe striations appear to still be there to my eye, even without GISD. GISD just seemed to be making them higher contrast/more visible. You say there's no texture on this? Are you using Smooth Normals? Might be a Normals issue...
That's what I thought at first, too. But the striations don't seem to be related to the mesh. They are consistent over the entire area, regardless of poly size and flow. They may be related to the UVs, but I'm not sure about that yet. Smooth normals are enabled.
So, this is interesting. To isolate the problem I imported the trolley model into a new, default scene and set the lighting and model angle to match the main scene. Camera has same settings, too. GISD values are default but with Ambient Occlusion enabled:
[attachimg=1]
The faint pattern you see here is the underlying mesh. Since the final camera position will be much further away, I'm not concerned about this. But otherwise it's clean. There are no striations.
I copied the render node from this scene into the original scene – to make sure everything matches – and rendered again from a similar angle. GISD settings are identical:
[attachimg=2]
I may be missing something here (pretty likely), but if I'm not then the problem isn't with the render node. It's something else in the environment.
Unless the GISD radius has something to do with it. Is this value really measured in screen units, Oshyan? (It says pixels.) Not physical units like cm or meters? Maybe the radius is causing the occlusion to bounce off surfaces that exist in the main scene but not the empty one.
The marks can be reduced by setting GISD to Global Illumination and adjusting the occlusion weight, so honestly, I'm not too worried about this. Once the object displacement and textures are applied you probably won't see it. But I'm curious to know what's going on here.