UV coordinates in Blender

This page is intended for a crash course in UV coordinates in Blender.

Links to good tutorials are welcome, as are tips from veterans, but the plan is to make a solid run-through for an absolute beginner, so if you're dealing with advanced topics likely to confuse a beginner please either leave them at the end, or perhaps consider a different page.

What is UV unwrapping?

Basically mapping a 2d texture onto a 3d mesh. Think of a world map's projection (like unpeeling an orange), or unfolding a cube to make a 2d surface

Objectives

The main things you are trying to balance when unwrapping:

• Size
  • Maximise use of texture space: You want to make your texture files as small as possible to avoid straining the game engine. Pack polygons into the map as tightly as you can, using space efficiently. A single part of the texture can be mapped to multiple polygons, and any faces internal to the model (which should be avoided where possible to prevent z-buffer issues) can be shrunk to a point.
  • Optimise detail: Parts of the mesh probably need more detail than others. The parts that should be highly detailed need more texture space, so should be made larger when unwrapped.
• Control distortion: You can distort polygons on the UV map for effect, but assume to begin with that you want to minimise distortion. If your polygon is a square, it should be square on the UV map.
• Alignment: Where texture detail crosses contiguous faces, it makes it much easier to line it up correctly if the faces are contiguous on the UV map too. For textures with 'grain' you may need to rotate parts of the map for it to look right.

Set up Blender

switch to UV unwrapping mode create file, add chequered pattern

Basic method

to do...

Tips

• If you've thoroughly stuffed it up and want to start again, switch to 'Default' screen layout and tab into object mode. Switch the panel on the right to 'Object Data'. Hit the minus sign next to UVMap to delete the map entirely.