Two new normal-based automasking modes. The first mode, "brush", compares vertex normals with the initial normal at the beginning of the brush stroke. The second, "view", compares vertex normals with the view normal. If "occlusion" is on then rays will be shot from each vertex to test if it is occluded by other geometry (note: this can be very slow).\ Only geometry inside the sculpt mesh is considered. Each mode has an associated angular limit and a falloff. Reviewed by: Julien Kaspar and Jeroen Bakker Differential Revision: https://developer.blender.org/D15297 Ref D15297