Is this normal?
Basically, it’s just in-Unity cubes that are instantiated many times… and when I do a CombineChildren on them I get Z fighting as if there are duplicate faces.
Is this to be expected? As far as I can see, you aren’t supposed to disable the objects’ own renderers, since the CombineChildren script already does that for you.
Bump! Still having this problem, on a wide variety of meshes. 
Bump.
Is CombineChildren just terribly bugged, or am I doing something wrong?
Ok some discoveries:
It appears to be some kind of problem with both a lit and an unlit triangle being drawn in the same location - the z fighting only appears on triangles that are receiving light from a directional light.
Changing from “Diffuse” shader to “Diffuse fast” shader appears to remove the z fighting, or at least make it non-visible.
Using a simple test project, the triangle count is unchanged when using CombineChildren - the z fighting seems to stem from something else.
Maybe this information can help someone to debug… maybe it’s a problem with the diffuse shader.
I’ve never experienced anything like that with CombineChildren…it doesn’t have any bugs as far as I know. Maybe post a project that displays a problem.
–Eric