Cut shape from the mesh using the material editor

[Etyuhibosecyu]

I want to cut some shape (for example, several cylinders) from the mesh such as shown here (black is what to cut):

But I don’t want to modify the actual mesh (which will make it heavy etc.), only the material. As for now, I use these nodes:

And I get this:

Since the mesh is just surface, inside it there is nothing. How to cut the cylinders correctly (as you see here in Blender)?

[sarahlenker]

Hi @Etyuhibosecyu!

Yeah, this is expected behavior. As you discovered, since a mesh is just a collection of surfaces rather than a solid body, masking out sections will indeed just make them holes.

My first suggestion would be to push back on not modeling the changes. If it is something relatively simple like this, this is much cheaper than the alternative (which we’ll go into in a sec). Generally, this is going to be the only way to get your desired result.

That being said, in very specific circumstances you can try using Parallax Occlusion Mapping (Linked tutorial for UE4). This will only really work on flat surfaces (breakdown as to why is here) and will not actually deform the geometry, so any holes on edges would still need to be modeled. Still, despite the limitations, it could be a potential solution for you. Again though, I would really look at both methods and weigh the costs, you’ll likely find that just modeling the changes are cheaper in both time and performance.

Here is another tutorial for a more in-depth look into POM for Unreal:

Parallax Occlusion Mapping | 5-Minute Materials [UE5]