PBR Material Displacement questions

Rendering
#1

Hi! I could not find a similar post but I have a note / question about PBR materials.

We found that the custom render mush had to be cranked way up for the PBR displacement to work first of all, but polysurfaces act strangely.

The faces all separate with displacement PBR applied. If I extractrendermesh, then weld the edges of that mesh it acts more normally.

Also the extractrendermesh with a PBR texture ignores the displacement, vs extracting the rendermesh with rhino displacement takes the displaced render mesh. Is this intentional?

Thanks! The PBR materials have been nice otherwise.!

displacement
displacement2008×1162 161 KB

#2

Rhino meshes are on ‘hard edges’ unwelded. That means that there is no connecting geometry there. A displacement map will therefor create gaps across such features.

For displacement maps to work properly you need high density meshes. The displacement mesh modifier you show on the top creates more geometry where needed in its preprocess step automatically (within the settings you give the command). This is something that a PBR material doesn’t do for you.

Low poly with render mesh shown on the left

image
image699×386 45.4 KB

High poly with render mesh shown on the left

image

Adobe Substance SBSAR support in Rhino 7
#3

So, what do I need to do in order to use Displacement PBR on, say, a Closed Extrusion, please?

Additionally - If using the Displacement in object properties instead of the Material, how would I keep the displacement within the edges of faces? In this case I’m trying to make large letters with faces of wavy sheet metal. Thx

#4

I have no good ideas here. I guess one work-around would be to extract the (dense) render mesh, and weld the unwelded edges. Then use that for rendering purposes.

I’m not sure I understand what you’re trying to achieve. Maybe some annotated screenshot or mockup would help.