Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: Radeon RX 580 Series ATI Technologies Inc. 4.5.13571 Core Profile Context 19.9.2 26.20.13003.1007
Broken: version: 2.81 (sub 15), branch: master, commit date: 2019-10-12 15:33, hash: rB95f020c853d6
Worked: Blender 2.79
I created this bug report at Sergey's request in devtalk.
Short description of error
Blender Subdivision modifier slower in different edit modes compare with blender2.79 Non-OpenSubDiv subdivision, No matter if the mesh is created entirely from quads, triangles or ngons. also it appear that needs a "start" time to activate the subdivision or when you move the vertex, something that didn't happen with 2.79 subdivision.
- edit quad mesh with subdivision
- edit lattice for an object with subdivision
Exact steps for others to reproduce the error
Open the shared files to test different conditions. The results in my test are
EDIT MODE mesh with quads
- 2.79: 50fps
- 2.80: 10fps
- 2.79: 19fps
- 2.80: 10fps
Armature mesh only with quads
- 2.79: 4,5fps
- 2.80: 6 fps
Also I provided other mesh file that show strange behaviors that I comment in next comment.
This problem is a extreme regression since it made impossible to work with blender2.80 with hard-surfaces, animation characters,... Specially when the undo-Z can need 4-5 seconds only when the scene have some subdivision objects and this problem disappear when you deactivate the subdivision.