Undo Super Duper Slow

I’ve been using Rhino since 1.0 and I’ve always counted on Undo as part of my work flow. It’s always been as fast as any other command. For example:

  1. If were to use the Hide command to hide an entire complex model, then
    2a) I could Unhide the model; or
    2b) I could Undo the Hide.
    …and the result is the same, with 2a and 2b taking the same amount of time…essentially, instant.

However, In the last month or so, option 2b (Undo) takes a long, long, long time…like 5 minutes long! 2a (Unhide) still works fine, instantly unhiding everything.

The problem gets worse the more complex the model.

I don’t have slow downs or memory or undo problems in any other programs (Photoshop, gaming, etc.), and everything else is as fast as usual. The problem seems to be limited to the Undo command in Rhino, exclusively.

I’m running:

  • MSI GT80 laptop
    -Version 5 SR14 64-bit (5.14.522.8390, 5/22/2017)

Any ideas how to fix this? It’s murdering my productivity going into 5 minute loops everytime I Undo and I’m developing a phobia about EVER pressing Ctrl-Z anymore!!

Hello - something of a shot in the dark but, just as a test, run Purge and purge all the available categories . Take a look at the command History and see just what was purged, then test the Undo… any difference?


Thanks Pascal, tried it, but no luck:

  • Command: Purge
  • Unused information to purge ( BlockDefinitions=Yes DimStyles=Yes Groups=Yes HatchPatterns=Yes Layers=Yes Linetypes=Yes Materials=Yes ):
  • Purged 2 unused block definitions.
  • Purged 8 unused dimension styles.
  • Purged 0 empty groups.
  • Purged 89 unused hatch patterns.
  • Purged 24 empty layers.
  • Purged 9 unused linetypes.
  • Purged 0 unused V4 materials.
  • Purged 0 unused V5 materials

Undo time was the same before and after :frowning:

Hello - one more thing to try- start Rhino in Safe Mode and see if the behavior is any different.


Any news on this? I see that on complex operations with many objects Undo can be slower than the previous calculation. Any reason why?

In example I have a script that samples an image and makes a halftone pattern in hatches and today tested it with 500x600 samples (adding 30 000 curves and hatches to the rhino document) and it all took 4 minutes to calculate, but then I forgout about the undo slowness and hit Ctrl-Z which has frozen Rhino. It has undo-ing-ed now for 5 minutes and I will terminate the process, but out of curiosity, why is Undo so extremely slow?