Before you begin painting, consider the following:
- Polygonal surfaces must have non-overlapping UVs that fit within 0 to 1 in the texture space. In general, Automatic Mapping produces UVs that can be used for painting. For details, see Introduction to polygons.
- NURBS models are usually made up of multiple patches, whereas polygonal models are often only made from a single mesh. When textures are assigned, each NURBS patch receives one texture, but by default a polygon receives only one texture for the entire mesh. This can result in insufficient texture resolution to get fine detail on a polygonal mesh. Increasing the texture size to the maximum results in slower performance, and may still not give sufficient resolution.
One solution is to partition the model by assigning several materials (for example, one for the head, one for the torso, one for the limbs). Each material on the mesh then receives its own texture. This has the added benefit of allowing you to work on part of the mesh at one time. To do this, right-click the material in Hypershade and select Assign Material to Selection. In this way you can also assign different size textures to different parts of the model if desired.
Note: The 3D Paint Tool does not deal with non-manifold geometry correctly.