Vertex Mass on cloth simulations no longer animatable. #88932

New Issue

Daniel Martynów · 2021-06-07T20:52:48+02:00

Daniel Martynów commented

2021-06-07 20:52:48 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.27

Blender Version
Broken: version: 2.93.0, branch: master, commit date: 2021-06-02 11:21, hash: 84da05a8b8
Worked: (2.92 back to 2.80 or longer)

Short description of error
Starting from 2.93 Vertex Mass value on cloth simulations is no longer possible to keyframe nor is it possible to add drivers to. This possibly breaks simulation addons and other simulation workflows that control that setting outside of the physics panel.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.27 **Blender Version** Broken: version: 2.93.0, branch: master, commit date: 2021-06-02 11:21, hash: `84da05a8b8` Worked: (2.92 back to 2.80 or longer) **Short description of error** Starting from 2.93 Vertex Mass value on cloth simulations is no longer possible to keyframe nor is it possible to add drivers to. This possibly breaks simulation addons and other simulation workflows that control that setting outside of the physics panel.

Daniel Martynów commented

2021-06-07 20:52:48 +02:00

Added subscriber: @DanteBoi

Evan Wilson commented

2021-06-08 00:43:09 +02:00

Added subscriber: @EAW

Evan Wilson commented

2021-06-08 00:43:09 +02:00

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

Evan Wilson commented

2021-06-08 00:43:09 +02:00

This function appears to have been removed with this commit: 4707c86179
Do you have an example blend showing how this worked in 2.92 and earlier?

This function appears to have been removed with this commit: 4707c86179 Do you have an example blend showing how this worked in 2.92 and earlier?

Daniel Martynów commented

2021-06-08 12:06:20 +02:00

Vertex Mass Driver 2.92.blend This should show it well. I use this type of drivers to control simulation settings on my rigged characters, it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway.

[Vertex Mass Driver 2.92.blend](https://archive.blender.org/developer/F10162371/Vertex_Mass_Driver_2.92.blend) This should show it well. I use this type of drivers to control simulation settings on my rigged characters, it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway.

Evan Wilson commented

2021-06-08 21:55:39 +02:00

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

Evan Wilson commented

2021-06-08 21:55:39 +02:00

Added subscribers: @ZedDB, @lichtwerk

Evan Wilson commented

2021-06-08 21:55:39 +02:00

it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway.

While the setting won't always update in real time, it will refresh to the driver's
value once the timeline is reset back to the start with shift+left arrow

Ah so your use case isn't updating the vertex mass while the simulation is running, it's using one value to adjust several cloth sims while experimenting to find the value you want.
@ZedDB @lichtwerk can you chime in with your thoughts on this?

> it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway. > While the setting won't always update in real time, it will refresh to the driver's > value once the timeline is reset back to the start with shift+left arrow Ah so your use case isn't updating the vertex mass while the simulation is running, it's using one value to adjust several cloth sims while experimenting to find the value you want. @ZedDB @lichtwerk can you chime in with your thoughts on this?

Daniel Martynów commented

2021-06-09 13:03:41 +02:00

In #88932#1173429, @EAW wrote:

it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway.

While the setting won't always update in real time, it will refresh to the driver's
value once the timeline is reset back to the start with shift+left arrow

Ah so your use case isn't updating the vertex mass while the simulation is running, it's using one value to adjust several cloth sims while experimenting to find the value you want.
@ZedDB @lichtwerk can you chime in with your thoughts on this?

The ideal thing is to have them update real time for better feedback but right now it works just fine with me having to restart the timeline to see the effects. I'm pretty sure Vertex Mass does refresh in real time, but there are other settings that don't quite work in real time, few months ago i did submit another report where drivers don't refresh the simulation instantly. #80828

> In #88932#1173429, @EAW wrote: >> it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway. > >> While the setting won't always update in real time, it will refresh to the driver's >> value once the timeline is reset back to the start with shift+left arrow > > Ah so your use case isn't updating the vertex mass while the simulation is running, it's using one value to adjust several cloth sims while experimenting to find the value you want. > @ZedDB @lichtwerk can you chime in with your thoughts on this? The ideal thing is to have them update real time for better feedback but right now it works just fine with me having to restart the timeline to see the effects. I'm pretty sure Vertex Mass does refresh in real time, but there are other settings that don't quite work in real time, few months ago i did submit another report where drivers don't refresh the simulation instantly. [#80828](https://developer.blender.org/T80828)

Philipp Oeser commented

2021-06-21 09:08:01 +02:00

Added subscriber: @dr.sybren

Philipp Oeser commented

2021-06-21 09:08:01 +02:00

In #88932#1173429, @EAW wrote:

it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway.

While the setting won't always update in real time, it will refresh to the driver's
value once the timeline is reset back to the start with shift+left arrow

Ah so your use case isn't updating the vertex mass while the simulation is running, it's using one value to adjust several cloth sims while experimenting to find the value you want.
@ZedDB @lichtwerk can you chime in with your thoughts on this?

Hm, this might seem like a valid usecase.
However the downside of having something appear as animatable (where in reality it is not) outweights the pros in my opinion.
If this is just meant to update a collection of objects to the same value, I think there are other ways to achieve this [while possible not as convenient, true]

I would be interested to hear another opinion on this: @dr.sybren: what do you think?

Oh, and btw. : we might dare supporting the real thing (having masses be really animatable while the simulation is running), see D11640: Fix #88188: Allow keyframing vertex mass in cloth sim

> In #88932#1173429, @EAW wrote: >> it's really useful to just have 1 slider for full clothing set which runs on the same settings anyway. > >> While the setting won't always update in real time, it will refresh to the driver's >> value once the timeline is reset back to the start with shift+left arrow > > Ah so your use case isn't updating the vertex mass while the simulation is running, it's using one value to adjust several cloth sims while experimenting to find the value you want. > @ZedDB @lichtwerk can you chime in with your thoughts on this? Hm, this might seem like a valid usecase. However the downside of having something appear as animatable (where in reality it is not) outweights the pros in my opinion. If this is just meant to update a collection of objects to the same value, I think there are other ways to achieve this [while possible not as convenient, true] I would be interested to hear another opinion on this: @dr.sybren: what do you think? Oh, and btw. : we might dare supporting the real thing (having masses be really animatable while the simulation is running), see [D11640: Fix #88188: Allow keyframing vertex mass in cloth sim](https://archive.blender.org/developer/D11640)

Sybren A. Stüvel commented

2021-06-29 12:26:38 +02:00

I feel that the title "Vertex Mass on cloth simulations no longer animatable" is misleading, as it was never really animatable to begin with. The fact that the animation system could be used to work around some other issue is nice, but not something we (IMO) should be actively supporting/promoting.

D11640: Fix #88188: Allow keyframing vertex mass in cloth sim seems like a simple enough solution. I don't know that much about the code in that area to give concrete feedback on the approach used. If that patch is acceptable, I'd much prefer that over other workarounds.

I feel that the title "Vertex Mass on cloth simulations no longer animatable" is misleading, as it was never really animatable to begin with. The fact that the animation system could be used to work around some other issue is nice, but not something we (IMO) should be actively supporting/promoting. [D11640: Fix #88188: Allow keyframing vertex mass in cloth sim](https://archive.blender.org/developer/D11640) seems like a simple enough solution. I don't know that much about the code in that area to give concrete feedback on the approach used. If that patch is acceptable, I'd much prefer that over other workarounds.

Philipp Oeser commented

2021-06-29 12:43:35 +02:00

Changed status from 'Needs Developer To Reproduce' to: 'Archived'

Philipp Oeser closed this issue

2021-06-29 12:43:35 +02:00

Philipp Oeser commented

2021-06-29 12:43:35 +02:00

If this usecase is not meant do be tackled with the animation/driver system, I think we should close this (even independently from D11640 being landed).

@DanteBoi : feel free to drop by https://blender.chat/ to discuss a suitable workaround for this usecase (outside the driver/animation system).

If this usecase is not meant do be tackled with the animation/driver system, I think we should close this (even independently from [D11640](https://archive.blender.org/developer/D11640) being landed). @DanteBoi : feel free to drop by https://blender.chat/ to discuss a suitable workaround for this usecase (outside the driver/animation system).

blender-admin commented

2021-07-15 15:58:34 +02:00

This issue was referenced by 59f9a5e6ac

This issue was referenced by 59f9a5e6ac6f5bff914204ef299cba27bb5016eb

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Vertex Mass on cloth simulations no longer animatable. #88932