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Undo takes 5 seconds, even on simple scenes.
Closed, DuplicatePublic

Description

System Information
Operating system: macOS Mojave 10.14.2
Graphics card: Radeon Pro 560X 4096 MB
Intel UHD Graphics 630 1536 MB

Blender Version
Broken:
2.80, 1b839e85e142, blender2.8, 2019-04-25
Download file is blender-2.80-1b839e85e142-OSX-10.9-x86_64

Short description of error

Undo takes a LOT of time on those tasks:
If I move an object and undo, resize and undo.
If I change something in a shader.
If I delete an object and undo.
When I undo a paint in Weight Paint, Vertex Paint and Texture Paint.

This doesn't happen on:
Sculpt Mode and Edit Mode.


Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).

Do some of those tasks to see how it slows down on specific actions.

Details

Type
Bug

Related Objects

Event Timeline

Can confirm that Undo actions are very slow. The only way to get around it is by using the Undo History if you want to go back several steps.

Sebastian Parborg (zeddb) triaged this task as Confirmed, Medium priority.Fri, Apr 26, 2:50 PM

It is slow because of the subdiv modifiers. @Sergey Sharybin (sergey) would it be possible to keep the subdiv cache on undo (if nothing has changed mesh wise)?

@Sebastian Parborg (zeddb), that is not possible since undo equals to re-opening the file from scratch. There is nothing you can preserve between global undo steps.

The only way to solve the issue is to speed up topology refinement step. However, this requires changes which are being worked on from OpenSubdiv side.

We've got other reports about Subsurf Modifier performance, will merge this one to them.

This is still happening even when objects don't have the Subsurface Modifier. Even if none of the objects in the project have it... And on those same tasks I said previously. Undo still works on Edit Mode and Sculpt Mode.