Animated particle emitter refuses transforms within simulation range #53245

New Issue

Konstantins Visnevskis · 2017-11-03T17:24:34+01:00

2017-11-03 17:24:34 +01:00

System Information
Operating system: Win8.1x64
Graphics card: 3xgtx580

Blender Version
Broken: 2.79, 2.82

Short description of error
An animated object with a particle system it is not properly transformed in the frames within the simulation range.
In Blender 2.79 the object jumps back to it's animated location on confirmation on hotkey or widget transformation.
In Blender 2.82 the object doesn't even transform, but its particles does.

Temporarily setting particle system Subframes parameter to 0 seems to be a workaround, eliminating the behavior.

Here is a gif showing the bug in 2.82 and 2.79:

Exact steps for others to reproduce the error

Open attached file
(G)grab move the emitter
particle-subframes.blend

In blender 2.82 you must change the visibility of objects. If you want to skip this step, use this file:
particle-subframes-283b.blend

**System Information** Operating system: Win8.1x64 Graphics card: 3xgtx580 **Blender Version** Broken: 2.79, 2.82 **Short description of error** An animated object with a particle system it is not properly transformed in the frames within the simulation range. In **Blender 2.79** the object jumps back to it's animated location on confirmation on hotkey or widget transformation. In **Blender 2.82** the object doesn't even transform, but its particles does. Temporarily setting particle system Subframes parameter to 0 seems to be a workaround, eliminating the behavior. Here is a gif showing the bug in 2.82 and 2.79: ![GIF.gif](https://archive.blender.org/developer/F8292488/GIF.gif) **Exact steps for others to reproduce the error** - Open attached file - (G)grab move the emitter [particle-subframes.blend](https://archive.blender.org/developer/F1090892/particle-subframes.blend) In blender 2.82 you must change the visibility of objects. If you want to skip this step, use this file: [particle-subframes-283b.blend](https://archive.blender.org/developer/F8366209/particle-subframes-283b.blend)

Konstantins Visnevskis commented

2017-11-03 17:24:34 +01:00

Changed status to: 'Open'

Konstantins Visnevskis commented

2017-11-03 17:24:34 +01:00

Added subscriber: @KonstantinsVisnevskis

blender-admin commented

2017-11-03 17:24:34 +01:00

#97447 was marked as duplicate of this issue

ronan ducluzeau commented

2017-11-04 12:09:06 +01:00

Added subscriber: @zeauro

ronan ducluzeau commented

2017-11-04 12:09:06 +01:00

There are lots of refreshing issues with particles.
Many modifications of emitter can conduct to an invalid cache. Color of cached frames in timeline becomes brighter when cache is invalid.
Calculate to Frame button is here to correct cache when it happens.

So, particles creator anticipated this kind of problems. But I am not sure how people who could have modified subframes will appreciate this.

There are lots of refreshing issues with particles. Many modifications of emitter can conduct to an invalid cache. Color of cached frames in timeline becomes brighter when cache is invalid. Calculate to Frame button is here to correct cache when it happens. So, particles creator anticipated this kind of problems. But I am not sure how people who could have modified subframes will appreciate this.

Konstantins Visnevskis commented

2017-11-04 15:09:48 +01:00

Particle cache, at least from how it looks, isn't exactly relevant here as the main problem is with inability to move the animated objects themselves.
However if the issue is tedious and as some claim the particle system will be rewritten in observable future, the workaround of temporarily disabling subframes could be acceptable in most cases.

Particle cache, at least from how it looks, isn't exactly relevant here as the main problem is with inability to move the animated objects themselves. However if the issue is tedious and as some claim the particle system will be rewritten in observable future, the workaround of temporarily disabling subframes could be acceptable in most cases.

ronan ducluzeau commented

2017-11-04 16:21:27 +01:00

Sorry for my lack of attention. I don't want to confuse people. It is definitely unexpected behaviour.

Concern about subframes is relatively recent.
At creation of particles system for 2.5, default cache step was set to 10 in order to have a fast feedback to animate objects.

And basically, subframes are described in manual only as a factor of quality improvement.
So, proobably most of blender users don't use them or modify emitter animation with subframes ON.

But they do not just allow to avoïd some unwanted explosions, they are correcting trajectories of particles which can result in totally new path of particles flow.
It is a legitimate request to be able to move emitters with subframes ON.

It has been taken into account in 2.8 proposals about physics as a nodal system. But maybe problem could be solved for a future 2.79a.

Sorry for my lack of attention. I don't want to confuse people. It is definitely unexpected behaviour. Concern about subframes is relatively recent. At creation of particles system for 2.5, default cache step was set to 10 in order to have a fast feedback to animate objects. And basically, subframes are described in manual only as a factor of quality improvement. So, proobably most of blender users don't use them or modify emitter animation with subframes ON. But they do not just allow to avoïd some unwanted explosions, they are correcting trajectories of particles which can result in totally new path of particles flow. It is a legitimate request to be able to move emitters with subframes ON. It has been taken into account in 2.8 proposals about physics as a nodal system. But maybe problem could be solved for a future 2.79a.

Germano Cavalcante commented

2020-01-21 19:21:07 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-01-21 19:21:08 +01:00

I can confirm the bug.
You cannot change the object's position (in some frames).
This is bad for an animator who wants to position an object in order to add a new keyframe.

Here is a gif showing the bug in 2.82 and 2.79:

I can confirm the bug. You cannot change the object's position (in some frames). This is bad for an animator who wants to position an object in order to add a new keyframe. Here is a gif showing the bug in 2.82 and 2.79: ![GIF.gif](https://archive.blender.org/developer/F8292488/GIF.gif)

Sybren A. Stüvel commented

2020-02-24 10:49:38 +01:00

Added subscriber: @dr.sybren

Sybren A. Stüvel commented

2020-02-24 10:49:38 +01:00

Changed status from 'Confirmed' to: 'Needs User Info'

Sybren A. Stüvel commented

2020-02-24 10:49:38 +01:00

When I open the example blend file with 2.8x (tested with 2.80, 2.82, and current master) I don't see any object:

@KonstantinsVisnevskis Can you re-test in the latest daily build (https://builder.blender.org/) to see if this still happens? If it does, please attach an example file that allows us to reproduce.

When I open the example blend file with 2.8x (tested with 2.80, 2.82, and current master) I don't see any object: ![image.png](https://archive.blender.org/developer/F8366101/image.png) @KonstantinsVisnevskis Can you re-test in the latest daily build (https://builder.blender.org/) to see if this still happens? If it does, please attach an example file that allows us to reproduce.

Konstantins Visnevskis commented

2020-02-24 12:26:28 +01:00

2.8x decided that viewport visibility is off, for some reason. The behavior is almost the same (object doesn't get transform display now).
particle-subframes-283b.blend

2.8x decided that viewport visibility is off, for some reason. The behavior is almost the same (object doesn't get transform display now). [particle-subframes-283b.blend](https://archive.blender.org/developer/F8366209/particle-subframes-283b.blend)

Campbell Barton commented

2020-03-04 02:34:13 +01:00

Changed status from 'Needs User Info' to: 'Needs Developer To Reproduce'