8fcf3e96fe
The thumb brush was updating the area normal per brush sample, which was making unstable sampled normals for setting the displacement direction when the vertices are moved too much from their original positions. Now it always uses the original normal except when using anchored strokes. In those cases, the normal always needs to be updated. Reviewed By: JacquesLucke Maniphest Tasks: T85079 Differential Revision: https://developer.blender.org/D10214