Hair particles lose position data when "Disconnect All" is used the first time from program load #47750

New Issue

Taylor Loz · 2016-03-10T20:22:42+01:00

Taylor Loz commented

2016-03-10 20:22:42 +01:00

System Information
Ubuntu 14.04LTS
Radeon HD 7400M

Blender Version
Broken: 2.76 48f7dd6 and 2.77 1e1118e
Worked: unknown

Short description of error
When a mesh has multiple hair particle systems and disconnect->all is run on a particle system all particles appear to set their location to object origin and loose rotation information.
(screenshots included)

If the user runs undo and selects disconnect hair again (all is already checked), the operation performs as expected without loss of information.

Exact steps for others to reproduce the error
From the provided .blend file:

Select either ParticleSystemA or ParticleSystemB (doesn't matter, unexpected behavior will occur with either one)
Disconnect Hair
Check "All hair" in the operator tab
At this point the unexpected behavior should occur

I have found that at this point undo (ctrl+z) then clicking disconnect "hair again" performs as expected

hairBug.blend

**System Information** Ubuntu 14.04LTS Radeon HD 7400M **Blender Version** Broken: 2.76 48f7dd6 and 2.77 1e1118e Worked: unknown **Short description of error** When a mesh has multiple hair particle systems and disconnect->all is run on a particle system all particles appear to set their location to object origin and loose rotation information. (screenshots included) If the user runs undo and selects disconnect hair again (all is already checked), the operation performs as expected without loss of information. **Exact steps for others to reproduce the error** From the provided .blend file: 1. Select either ParticleSystemA or ParticleSystemB (doesn't matter, unexpected behavior will occur with either one) 2. Disconnect Hair 3. Check "All hair" in the operator tab 4. At this point the unexpected behavior should occur I have found that at this point undo (ctrl+z) then clicking disconnect "hair again" performs as expected [hairBug.blend](https://archive.blender.org/developer/F289370/hairBug.blend) ![hairBugBefore.png](https://archive.blender.org/developer/F289371/hairBugBefore.png) ![hairBugAfter.png](https://archive.blender.org/developer/F289373/hairBugAfter.png)

Taylor Loz commented

2016-03-10 20:22:42 +01:00

Changed status to: 'Open'

Taylor Loz commented

2016-03-10 20:22:42 +01:00

Added subscriber: @zmaster587

perfection cat commented

2016-03-11 03:04:02 +01:00

Added subscriber: @sindra1961

perfection cat commented

2016-03-11 03:04:02 +01:00

Even all versions in here were the same results.
(2.64a/2.69/2.74/2.76b)

win10 64bits

Even all versions in here were the same results. (2.64a/2.69/2.74/2.76b) win10 64bits

Bastien Montagne commented

2016-03-12 18:55:27 +01:00

Added subscribers: @Sergey, @ideasman42, @mont29

Bastien Montagne commented

2016-03-12 18:55:27 +01:00

There are two issues here, both related to internal undo/redo performed by the operator when you edit its settings:

the 'all hair' option in disabled state would not work at all except first time (due to how active psys is found in current code, easy to fix, will do soon).
much more annoying, after the first undo/redo, psmd->dm_final is NULL (because undo/redo == file save/read, which clears this runtime-only data, and operator gets executed before object is updated again). This means psys_mat_hair_to_global() returns default unit matrix, hence the bad result.

Only way to fix point 2) would be to force an update (depsgraph evaluation) before re-running the operator, @Sergey, @ideasman42, think this is not possible nor desired in current design?

There are two issues here, both related to internal undo/redo performed by the operator when you edit its settings: 1) the 'all hair' option in disabled state would not work at all except first time (due to how active psys is found in current code, easy to fix, will do soon). 2) much more annoying, after the first undo/redo, `psmd->dm_final` is NULL (because undo/redo == file save/read, which clears this runtime-only data, and operator gets executed before object is updated again). This means `psys_mat_hair_to_global()` returns default unit matrix, hence the bad result. Only way to fix point 2) would be to force an update (depsgraph evaluation) before re-running the operator, @Sergey, @ideasman42, think this is not possible nor desired in current design?

Sergey Sharybin commented

2016-03-14 07:27:19 +01:00

@mont29, think it makes more sense to simply disable re-do for such operators and have two separate invoke buttons for it. Adding depsgraph evaluations just to deal with a broken system is not really nice way.

P.S. Actually, if ever we'll run into such situation again, think it'll make more sense to put DM into undo stack. That's more mem usage, but more instant redo and opens possibility of caching scene on SSD disks without huge penalty.

@mont29, think it makes more sense to simply disable re-do for such operators and have two separate invoke buttons for it. Adding depsgraph evaluations just to deal with a broken system is not really nice way. P.S. Actually, if ever we'll run into such situation again, think it'll make more sense to put DM into undo stack. That's more mem usage, but more instant redo and opens possibility of caching scene on SSD disks without huge penalty.

blender-admin commented

2016-03-14 21:04:30 +01:00

This issue was referenced by a078fe3539

This issue was referenced by a078fe35396a34c8f6440e22c37a3b27e0c1f61a

Bastien Montagne commented

2016-03-14 21:14:50 +01:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2016-03-14 21:14:50 +01:00

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Hair particles lose position data when "Disconnect All" is used the first time from program load #47750