Force field absorption not working with rigid bodies unless a particle system is present #103571

New Issue

Peter Goodman · 2022-12-31T18:34:37+01:00

Peter Goodman commented

2022-12-31 18:34:37 +01:00

System Information
Operating system: Microsoft Windows [Version 10.0.19042.2251]
Graphics card: Nvidia Quadro RTX 4000 (driver 512.36)

Blender Version
Broken: 2.83.20; 2.93.13; 3.3.2; 3.4.1
Worked: 2.79

Short description of error
Absorption setting on collision objects and force fields does not work with rigid bodies unless a particle system is also added. Previously in 2.79 this works on rigid bodies whether a particle system is present or not.

Exact steps for others to reproduce the error
Load the attached blend file in blender version 2.83.20 or later (it is saved in 2.79 and opens fine in any newer version)
2022-12-31_rigid_body_field_absorption_blender2-79.blend

See attached image:

Press SPACE to play the animation. Note that world gravity is disabled, the downward motion is caused by the plane force field below.

Initially you will see the left hand cube ('Cube') and particles above it not moving because the block beneath it ('Cube.001') has the physics properties->collision->field absorption set to maximum, thus blocking the force field below affecting anything above 'Cube.001' in the positive z direction (the force field also has the Absorption setting ticked). The cube on the right ('Cube.002') is not shielded by 'Cube.001' so is affected by the force field. This is the expected behaviour.

If you delete the particle emitter plane and repeat the playback, the cube on the left now falls the same as the one on the right, ie the absorption of 'Cube.001' is no longer preventing the force field from affecting it. This is not the expected behaviour.

If you reopen the file in blender 2.79 and repeat this, the absorption works whether the particle sytem is there or not (ie 'Cube' is not affected by the force field).

**System Information** Operating system: Microsoft Windows [Version 10.0.19042.2251] Graphics card: Nvidia Quadro RTX 4000 (driver 512.36) **Blender Version** Broken: 2.83.20; 2.93.13; 3.3.2; 3.4.1 Worked: 2.79 **Short description of error** Absorption setting on collision objects and force fields does not work with rigid bodies unless a particle system is also added. Previously in 2.79 this works on rigid bodies whether a particle system is present or not. **Exact steps for others to reproduce the error** Load the attached blend file in blender version 2.83.20 or later (it is saved in 2.79 and opens fine in any newer version) [2022-12-31_rigid_body_field_absorption_blender2-79.blend](https://archive.blender.org/developer/F14102425/2022-12-31_rigid_body_field_absorption_blender2-79.blend) See attached image: ![rigid_body_absorption3.PNG](https://archive.blender.org/developer/F14102440/rigid_body_absorption3.PNG) Press SPACE to play the animation. Note that world gravity is disabled, the downward motion is caused by the plane force field below. Initially you will see the left hand cube ('Cube') and particles above it not moving because the block beneath it ('Cube.001') has the physics properties->collision->field absorption set to maximum, thus blocking the force field below affecting anything above 'Cube.001' in the positive z direction (the force field also has the Absorption setting ticked). The cube on the right ('Cube.002') is not shielded by 'Cube.001' so is affected by the force field. This is the expected behaviour. If you delete the particle emitter plane and repeat the playback, the cube on the left now falls the same as the one on the right, ie the absorption of 'Cube.001' is no longer preventing the force field from affecting it. This is not the expected behaviour. If you reopen the file in blender 2.79 and repeat this, the absorption works whether the particle sytem is there or not (ie 'Cube' is not affected by the force field).

Peter Goodman commented

2022-12-31 18:34:37 +01:00

Added subscriber: @badbunny_uk

Peter Goodman changed title from ~~Force field absorption on rigid bodies not working unless a particle system is present~~ to Force field absorption not working with rigid bodies unless a particle system is present

2022-12-31 19:53:31 +01:00

Germano Cavalcante commented

2023-01-02 20:46:04 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2023-01-02 20:46:04 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Germano Cavalcante commented

2023-01-02 20:46:04 +01:00

I can confirm.
It appears that the effect of the collision modifier is lost if there is no particle system in the scene.
It seems to be a depsgraph issue.

I can confirm. It appears that the effect of the collision modifier is lost if there is no particle system in the scene. It seems to be a depsgraph issue.

Bastien Montagne added this to the Core project 2023-02-09 15:43:54 +01:00

Bastien Montagne removed this from the Core project 2023-02-09 18:20:29 +01:00

Philipp Oeser removed the

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Force field absorption not working with rigid bodies unless a particle system is present #103571