'Stickyness' option in collision objects causes particles to oscillate between sub frames #52933

New Issue

Andy Goralczyk · 2017-09-28T11:10:18+02:00

Andy Goralczyk commented

2017-09-28 11:10:18 +02:00

System Information
Ubuntu Linux with XFCE
Kernel 3.13.0-44-generic

Blender Version
Broken: 2.79 2a74f36
Worked: (afaik never)

See the attached file. particles_stickyness.blend
A particle system is colliding with a plane, which has the value 'Stickiness' (which I don't even know if it works) set to 10.

This causes the particles to oscillate between above the plane and below, but only between subframes. On the frames they are seemingly colliding with the plane. Hence you don't see the issue appear in the viewport, but if rendering with motion blur, the particles appear blurred, but static.

To debug this in the attached file, I have set 'Show sub frames' enabled in the timeline editor.
Baking the particles with higher sub frame count does not fix this, so I am guessing it is related to how the collision interacts with the Stickiness value.

Cheers!
Andy

**System Information** Ubuntu Linux with XFCE Kernel 3.13.0-44-generic **Blender Version** Broken: 2.79 2a74f36 Worked: (afaik never) See the attached file. [particles_stickyness.blend](https://archive.blender.org/developer/F899568/particles_stickyness.blend) A particle system is colliding with a plane, which has the value 'Stickiness' (which I don't even know if it works) set to 10. This causes the particles to oscillate between above the plane and below, **but only between subframes**. On the frames they are seemingly colliding with the plane. Hence you don't see the issue appear in the viewport, but if rendering with motion blur, the particles appear blurred, but static. To debug this in the attached file, I have set 'Show sub frames' enabled in the timeline editor. Baking the particles with higher sub frame count does not fix this, so I am guessing it is related to how the collision interacts with the Stickiness value. Cheers! Andy

Andy Goralczyk commented

2017-09-28 11:10:18 +02:00

Changed status to: 'Open'

Andy Goralczyk commented

2017-09-28 11:10:18 +02:00

Added subscriber: @eyecandy

ronan ducluzeau commented

2017-09-28 14:32:24 +02:00

Added subscriber: @zeauro

ronan ducluzeau commented

2017-09-28 14:32:24 +02:00

Here a .blend to demonstrate that stickiness works.
particles_stickyness_fluid.blend

It was introduced to control particles with a "Fluid" physics type.

I confirm that problem is visible by moving time cursor with LMB in timeline.

I thought that subframes was ignored while rendering.
Generally, we are using metaballs to render fluid particles.

Here a .blend to demonstrate that stickiness works. [particles_stickyness_fluid.blend](https://archive.blender.org/developer/F901786/particles_stickyness_fluid.blend) It was introduced to control particles with a "Fluid" physics type. I confirm that problem is visible by moving time cursor with LMB in timeline. I thought that subframes was ignored while rendering. Generally, we are using metaballs to render fluid particles.

Ray molenkamp commented

2017-10-07 02:23:07 +02:00

Added subscriber: @LazyDodo

Ray molenkamp commented

2017-10-07 02:23:07 +02:00

Changed status from 'Open' to: 'Archived'

Ray molenkamp closed this issue

2017-10-07 02:23:07 +02:00

Ray molenkamp self-assigned this 2017-10-07 02:23:07 +02:00

Ray molenkamp commented

2017-10-07 02:23:07 +02:00

This is a known limitation, particles might get some love in 2.8 until that time i'm going to have to archive this ticket.

cmto commented

2023-11-10 01:39:19 +01:00

@LazyDodo

This is a known limitation, particles might get some love in 2.8 until that time i'm going to have to archive this ticket.

This is still a limitation 6 years later -- is there any love on the horizon? :)

@LazyDodo > This is a known limitation, particles might get some love in 2.8 until that time i'm going to have to archive this ticket. This is still a limitation 6 years later -- is there any love on the horizon? :)

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'Stickyness' option in collision objects causes particles to oscillate between sub frames #52933