Confirming that UVs are positioned correctly is critical if you want the textures to appear correctly on the surfaces of your mesh. One method of confirming the UV placement is to apply a temporary texture map, which you can then evaluate on your model for possible distortions. There are two such shaders made specifically for this purpose: checker and distortion.
To apply a temporary map to a UV shell
- Select the mesh.
- Open the UV Editor.
- Click the
Checker Shader (
) or
Distortion Shader (
) button.
The checker shader allows you to evaluate distorted areas by seeing where the colored squares are distorted.
The distortion shader applies specific colors to areas where the UV shell is stretched or compacted (red and blue respectively). To avoid distortion, you'll want to move UVs until the majority of the UV shell is white.