UV unwrapping is the process of creating a UV map. A UV map projects 2D textures onto the surface of a 3D model.
It is best practice to keep UV islands as straight as possible.
Note: A UV island is a connected group of polygons in a texture map.
The reasons for keeping UV islands as straight as possible are:
- It makes packing UV islands easier and less space is wasted.
- A straight UV helps to reduce the staircase effect happening on textures.
- On mobile platforms, texture space is limited. This is because the texture size is usually smaller on a mobile platform than on a games console or a PC. Good UV packing ensures that you get the best resolution from your texture.
- You might consider having a slightly distorted UV by keeping the UV straight, in order to have better quality texture overall.
Place UV seams in places that make them not too visible, for visual quality purposes. This is because the texture seam can look bad on a model. Therefore, split UV islands where the edges are sharp and have a small space between the UV islands. This helps later on to create better normal maps through the baking process.
The following image shows an example of how to use UV unwrapping to maximize texture space: