So what was the answer to this? I have the same problem on any terrain I build from World Machine and the holes seem random. I’ve seen plenty of places where the angles are just the same where I’m getting these exact random holes so it doesn’t seem to be the problem of sharp angles etc… besides this wouldn’t create these strange perfect holes like this. Something else is going on and it doesn’t happen on regularly sculpted terrain… it’s only when you import a height map and build lighting. I’ve seen others do it without this problem so why are we? As soon as I import the height map in and build lighting, it happens every single time and it’s nothing to do with the materials either from what I can tell as I’ve been round and round with every possible issue I can find with this and they are only related to blended layers within the material on the landscape etc. I’m getting this immediately after building the lighting right after importing the height map in and creating the terrain from it.