V-Ray for Rhino: Weird dark patches on ground/floor material

[Serafim A]

Hello,

I'm using McNeel Rhinoceros 7 with latest V-Ray for Rhino.

I have an issue with my 3D model and I've Googled so much but cannot seem to find a solution to this problem I'm having.

When in Interactive Render mode and also when doing proper render, the ground/floor material/geometry in my 3D model get these weird dark patches (see images). I just don't understand why. The green planar geometry is using a carpet material, and the grey planar geometry is using a concrete material. I'm hoping any of you might now why I'm getting these weird dark patches on my geometry.

Thank you so much
Serafim

[James Vella]

Looks like the faces are not triangulated/quad. Try putting a tesselate modifier or the rhino equivalent.

 

Example:

Edited April 4, 2022 by James Vella

[Francisco Penaloza]

That looks more like double geometry to you need to rebuild the UV on that plane.