Best way to go about material size issues and vertex painting on complex mesh?

Hello all,

I’m starting to see vertex painting as the best way to go about making my level appear the way I want it to. In summary; I am making a historical building in 3DS Max which shall have materials created to make it appear new, which I then plan to dirty down in UE4 by vertex painting pollution etc over it. The wall I am making shall be a repeating structure, and so to break up the ‘repeated look’ I want to vertex paint to make each section unique.

Trouble is; I’m not sure what the best method would be to prepare my mesh for vertex painting. I am connecting more vertices and creating edges where I think it would work well to paint, but how far should I go? This won’t just be a simple case of ‘slap on a brick material and call it done’. No, I am making it ‘brick-accurate’, meaning bricks are going to be placed at very specific places. Each brick in reality, when looking at real world aesthetics, has its own level of grime and pollution.

The question I am leaning into is; if I know where every brick should go, should I outline every brick onto the walls? This would certainly ramp up the poly count, but I am guessing it will let me really focus in on where I paint grime and pollution. (Would also make it easier for material mapping I guess). I have already done this with the stonework on the mesh as it’s easier and doesn’t add much poly-wise, but bricks would.

If this is not the best scenario, then what is the best way to break up my large polys into smaller ones in order to really make each section unique in engine?

I’ll post a picture as demonstration.

The second question I have is;

If I am making this material so specific, I have to have it mapped exactly to the polys. I can’t just throw on a repeated material. If I want these sections to be a really decent resolution, cramming all of the unwraps into one box is going to call for one hefty file. Am I better off using multi-sub materials in this instance? I have played around with these before, and they were promising, but with the level of detail I am attempting, we’re looking at around 5+ materials for one mesh, which would include their own albedos, normals, roughess, AO etc…and also the vertex paint maps. Is this something recommended?

These questions have been bothering me for a while, and I just can’t get my inexperienced head around possible, viable solutions.

I am hoping someone will have an answer tucked away for me somewhere. I would really appreciate it.

I am attaching a screenshot of the mesh in question.