Keyframing Vertex Mass in Cloth Simulation doesn't have any effect #88188

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Robert Sheldon · 2021-05-11T00:24:59+02:00

Robert Sheldon commented

2021-05-11 00:24:59 +02:00

System Information
Operating system: Windows-10-10.0.21370-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.25

Blender Version
Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: 02948a2cab
Worked: I can't find if it ever worked

Short description of error
Keyframing a vertex mass change does not affect the simulation; only the weight at the start affects the simulation. pausing the simulation and manipulating vertex mass works as expected however; the new mass applies to the target and it deforms differently. I've illustrated this with a pin group below, but it still occurs without a pin group, when colliding with a plane instead. It also happens on 3.0.0.

Exact steps for others to reproduce the error

Create an icosphere with 3 divisions
add the top 6 vertices to a vertex group "cloth pin target" with a weight of 1
create a cloth simulation on the icosphere
add "cloth pin target" as pin shape to cloth simulation
keyframe vertex weight - eg 2kg on frame 50, 10kg on frame 90
run simulation

I've attached this example file below:

Keyed vertex weight.blend

I would very much like this to work, but I realize it may have not been intended to work like this. It's confusing that I'm able to set the keyframes if that is the case.

Thank you!

**System Information** Operating system: Windows-10-10.0.21370-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.25 **Blender Version** Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: `02948a2cab` Worked: I can't find if it ever worked **Short description of error** Keyframing a vertex mass change does not affect the simulation; only the weight at the start affects the simulation. pausing the simulation and manipulating vertex mass works as expected however; the new mass applies to the target and it deforms differently. I've illustrated this with a pin group below, but it still occurs without a pin group, when colliding with a plane instead. It also happens on 3.0.0. **Exact steps for others to reproduce the error** 1. Create an icosphere with 3 divisions 2. add the top 6 vertices to a vertex group "cloth pin target" with a weight of 1 3. create a cloth simulation on the icosphere 4. add "cloth pin target" as pin shape to cloth simulation 5. keyframe vertex weight - eg 2kg on frame 50, 10kg on frame 90 6. run simulation I've attached this example file below: [Keyed vertex weight.blend](https://archive.blender.org/developer/F10077413/Keyed_vertex_weight.blend) I would very much like this to work, but I realize it may have not been intended to work like this. It's confusing that I'm able to set the keyframes if that is the case. Thank you!

Robert Sheldon commented

2021-05-11 00:24:59 +02:00

Added subscriber: @rsheldiii