I’m quite new at Unreal Engine, but if I make a series of models for maya, layout their UV’s and so on, what would be an ideal texture resolution to create, I could do each model with a resolution of 1920 x 1080, but since i usually layout the UV’s for all models in the same UV file (if it’s more then one model in the same scene) what resolution would be ideal to use then?
A power of 2 resolution for bother width and height is highly recommended since this allows mip maps to be created (so if you have a 2048x2048 texture, the engine will stream a 1024x1024, 512x512, 256x256, 128x128, 64x64… texture based on the view distance and screen size). 2048 for mid scale objects is as far as my understanding goes the industry standard nowadays (on PC at least), 4096 is great, and 8192 is a bit too much (BTW the max texture resolution that will get streamed is 4096 unless you edit the Engine.ini). For the size of the texture I recommend trying some and play with it to see which resolution is optimal.
As Vinz says, always go for a power-of-2 sized texture. As for the actual resolution of the texture, it depends fully on what the object in question is. If it is something you will see up close or it is very big, you need higher resolution, than if it is a box of matches or only seen from very far away. A good rule of thumb is to always create your textures in at least twice the size you expect you need them at, then you got some leeway if you feel you need to upres it at some point.
hint: Power of 2 isn’t exactly square; You can have P^2 textures that are 1024x512, 256x2048, 64x512, etc… And they are still power 2 textures that can be compressed and streamed by the engine.
For ios you still want to keep texture squares. PVRTC only work with square sizes.