To be more specific, I'm making a glass table that consists of two parts: the legs part, which has a metallic material, and the glass top, which has a glass material. Do I have to UV unwrap them, or it's pointless if there is no texture applied to them?
As I know, if I want to import it to a game engine, they need at least one UV map for the lightmap. Though I'm not sure.
So please tell me if I need them or not. Thank you
Realtime oriented lighting systems used in games usually rely on UV maps to bake pre-calculated rendering attributes (even when the artist do not provide diffuse/normal maps). Depending on the game engine you are using, unwrap may happen automatically.
Automatic unwrap may result in poor/inefficient UV maps so, as a general rule, manually unwrap and provide your own UVs.
You don't need to UV unwrap the mesh if you can use the procedural texture coordinates like Generated or Object to get the material you want. This applies mainly to within Blender. If you are exporting to another app, like a game engine, you'll need to use the most compatible texture coordinate mode, which may in fact, be UV.
As far as Unity is concerned, a UV map isn't necessary for your mesh. You should be able to import it just fine and even apply simple textures to your object and tile them. Furthermore, Unity can generate lightmaps on its own, so that's not an issue either.
You don't if you're using unity like others but im not sure about other game engines. I would think not because the only thing a uv is used for from my understanding is a texture . if you have no texture you need no uv.
