Added a new api function to stich multires grids
on specific faces in a mesh,
subdiv_ccg_average_faces_boundaries_and_corners,
and changed multires normal calc to use it.
VTune profiling showed that this was a major
performance hit once you get above 10,000 or so
base mesh faces and/or have a high number of
subdivision levels.
Here's a video comparing the difference. Note the
bpy.app_debug switch is not in the final commit.
{F10145323}
And the .blend file:
{F10145346}
Reviewed By: Sergey Sharybin (sergey)
Differential Revision:
https://developer.blender.org/D11334
482465e18a