[Phil Leide]

They are both in the “Mesh” menu after the object is imported.

Mesh -> Normals -> Reverse Normals
Mesh -> Commands -> Optimize

When you use Optimize, there is a small box to the right of the menu. Click on it to bring up the options and change tolerance to 0.

[Phil Leide]

I am having similar problems with some OBJ files I am importing to render. Same idea – originally from CAD, converted to OBJ.

The workflow that I’ve found that works best for me right now is this:
1) Import OBJ
2) Reverse Normals
3) Optimize, with the tolerance set to 0
4) Apply textures
5) Set Phong to 5 degrees
6) Test render

This fixes most of the issues major banding issues, but sometimes it causes weird marks on flat surfaces elsewhere in the model. If it does that, sometimes playing with the Phong settings helps.

I’ve yet to find something that works 100% of the time. If you find anything else that helps, feel free to share.

[Phil Leide]

I actually just fixed the issue, after much Googling and playing with settings. I used Mesh -> Optimize on the model, but changed the tolerance to 0. From that point, I just played with the Phong settings until I got one that worked.

Guess it wasn’t a V-Ray specific issue after all.

I’ve been working on this issue for weeks. So glad it’s finally fixed.