Rigging & Animation

Weight Painting

Painting how bones move vertices

Also known as: Skin weights · Vertex weights · Bone influence · Skin weight painting

Definition

Weight painting is the process of painting how strongly each bone influences each vertex of a skinned mesh, with values from 0 to 1. Where a vertex is fully influenced by one bone it moves with it, and where two bones overlap it blends between them, which is what makes elbows, shoulders and knees bend smoothly. The weights for a vertex add up to 1, and game engines limit how many bones can influence one vertex, commonly four.

In production

Paint with a soft brush, work from the joint outward, and test with extreme poses from the animation, not only the rest pose. Mirror the weights, then fix the center. Remove very small influences and normalize so the engine does not drop the wrong ones. Where weights alone cannot give a good shape, use corrective blend shapes or helper bones, and always check the deformation in the engine, since influence limits can change the result.