Hello,
When I have a big wall or floor, I scale it much bigger than the texture in UV mapping, and it automatically repeats the texture.
However, what if I want to gather all different floors and walls into an atlas ?
Is there some way to tell the system to repeat one particular part of the image ?
I hope you understand what I am talking about ! Thanks in advance!
Dimitris,
Greece
You have to split the geometry into tiles and overlap those in your atlas UVs.
Thanks for your reply,
In my case it is not worth the trouble because the wall is hundreds of times larger than the brick texture… oh well…
I am sure there is a way using material nodes and a little math (Modulo function should do the trick). I could not find the example in my collection, so I hope the hint is enough for you to get started.
try using a cycles image node in “box” project mode, and warp the XYZ cords as @AeroLynx suggested - by using seperate rgb (operate on r g b) -> combine again before pluggin into the image texture node.
I am not sure if what @BluePrintRandom suggested works, maybe there is a misunderstanding.
However, below is a little example, I think I made working what you are trying to achieve.
Have a look at this incredible piece of artwork in the UV image Editor. Let’s assume you want to repeat the star. I unwrapped a single plane and played around with nodes until I came up with the shown setup. It just repeats it using the modulo operator on both channels after it is multiplied by a factor of your choice. This method only uses ONE plane instead of one for each repetition of the texture as suggested by @LDAsh, so I expect it to be less heavy in terms of computation.
The screenshot contains everything you need to know.
My reply was based on the assumption that it would go into a realtime 3D engine, since making an atlas for an offline render doesn’t make much sense to me, but then I didn’t consider BGE (or variants) at all, so that’s pretty interesting. The general consensus is that polycount (for the sake of repeating UVs for an atlas) is not as much of a worry as batches and drawcalls that can arise from have 1000s of tiny textures everywhere, but ultimately there is a “goldilocks-zone” with balancing that out. If there’s a similar thing that can be done with say Unity or UE, I’d be interested to know.
now it’s hearts all the way around 
what can this be used for? having multiple tile textures and using vertex color to mix them,
with a single texture
and you can do anything in GLSL in most engines @LDAsh
This thread covers a similar texture atlas situation, it may be helpful:
owwwww ! 8-D
this topic is damn interresting !!!
I keep it in sight and will try is soon.
Thanks a lot SterlingRoth 
and happy blending !
