Bug: disappearing surfaces

Unity Engine
1

I have a very strange bug. I have a car rim in 3ds max, and three materials applied to it. I export this rim to Unity and… it has only 2 materials. I’ve tried to create a box and apply all three materials to it… works fine. But it doesn’t work with the rim. Any ideas why?

I’ve forgot to mention. 3rd material imports to unity, but doesn’t apply to rim. So the part of rim, which should have this material just disappeared.

2

Ok, deleting the whole project and rebuilding it solved the problem… I hope such things will now happen too often. Because it is a lot of headache, when you have a large-scale project and have to rebuild everything.