[Mantaflow] Particles not generated on Plane object #73161

New Issue

Miro Horváth · 2020-01-16T12:50:30+01:00

Miro Horváth commented

2020-01-16 12:50:30 +01:00

System Information
Operating system: W10
Graphics card: nVidia 970

Blender Version
Broken: blender 2.82 3edd8d5b07 windows64

Short description of error
Particles not generated on Plane object

Exact steps for others to reproduce the error
Open the attached blend file and hit Bake, you should see that particles don't get generated.
When you rotate Plane object either around X or Y axis a bit(or in Edit mode) and rebake, particles get generated. Rotating around only Z axis doesn't fix the problem.

Seems like if plane's dimension in one of the axis is 0 it doesn't work.
test01.blend

**System Information** Operating system: W10 Graphics card: nVidia 970 **Blender Version** Broken: blender 2.82 3edd8d5b075a windows64 **Short description of error** Particles not generated on Plane object **Exact steps for others to reproduce the error** Open the attached blend file and hit Bake, you should see that particles don't get generated. When you rotate Plane object either around X or Y axis a bit(or in Edit mode) and rebake, particles get generated. Rotating around only Z axis doesn't fix the problem. Seems like if plane's dimension in one of the axis is 0 it doesn't work. [test01.blend](https://archive.blender.org/developer/F8281403/test01.blend)

Miro Horváth commented

2020-01-16 12:50:30 +01:00

Added subscriber: @MiroHorvath

Germano Cavalcante commented

2020-01-17 13:28:52 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-01-17 13:28:52 +01:00

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

Germano Cavalcante commented

2020-01-17 13:28:52 +01:00

At first I thought the problem is that the inflow is an unclosed mesh.
But even enabling Is Planar, I can't make the simulation work.

At first I thought the problem is that the inflow is an unclosed mesh. But even enabling `Is Planar`, I can't make the simulation work.

ronan ducluzeau commented

2020-01-19 21:10:31 +01:00

Added subscriber: @zeauro

ronan ducluzeau commented

2020-01-19 21:10:31 +01:00

There is a Surface Thickness setting under Flow Source Subpanel.

It is set to zero by default for Quick Liquid set-up. That is what you want when you use a closed mesh as a liquid volume.
But if you want to use a plane as an Inflow, you have to give a little thickness.
A value of 0.00001 is sufficient. In fact, it does not matter how small it is.
You just have to set a Surface Thickness higher than zero.

There is a Surface Thickness setting under Flow Source Subpanel. It is set to zero by default for Quick Liquid set-up. That is what you want when you use a closed mesh as a liquid volume. But if you want to use a plane as an Inflow, you have to give a little thickness. A value of 0.00001 is sufficient. In fact, it does not matter how small it is. You just have to set a Surface Thickness higher than zero.

Miro Horváth commented

2020-01-20 18:05:59 +01:00

Thanks for the hint @zeauro, but still it's a weird user experience that I have to set non-zero Surface Thickness when plane has no rotation, but once Plane is rotated(either X or Y axis) it works even without non-zero Surface Thickness.

Stefano Lazzaroni commented

2020-02-04 09:08:37 +01:00

Added subscriber: @Lazza

Stefano Lazzaroni commented

2020-02-04 09:08:37 +01:00

I could be incorrect but... I've tried to understand what mantaflow does and it seems to "spawn" particles from a Volume. It refresh every steps and check if there's more space to put particles in. Since the plane has no Volume there are not cells to spawn particles. I think that all that problem will be cleared with a nice written documentation. It's not easy to guess what a software does only from the control panel.
By the way the surface thinkness it's been replaces with another parameter. Now it works. With a sufficient value (depending on resolution) it creates enough "virtual" space on the surface and mantaflow treat it as a Volume instead of a planar surface.
These are only MY consideration so don't take them as the pure truth. Just try it yourself

I could be incorrect but... I've tried to understand what mantaflow does and it seems to "spawn" particles from a Volume. It refresh every steps and check if there's more space to put particles in. Since the plane has no Volume there are not cells to spawn particles. I think that all that problem will be cleared with a nice written documentation. It's not easy to guess what a software does only from the control panel. By the way the surface thinkness it's been replaces with another parameter. Now it works. With a sufficient value (depending on resolution) it creates enough "virtual" space on the surface and mantaflow treat it as a Volume instead of a planar surface. These are only MY consideration so don't take them as the pure truth. Just try it yourself

Johan Walles commented

2020-02-18 07:00:01 +01:00

Added subscriber: @Walles

Sebastián Barschkis commented

2020-03-27 17:02:07 +01:00

Added subscriber: @sebbas

Sebastián Barschkis commented

2020-03-27 17:02:07 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Sebastián Barschkis closed this issue

2020-03-27 17:02:07 +01:00

Sebastián Barschkis self-assigned this 2020-03-27 17:02:07 +01:00

Sebastián Barschkis commented

2020-03-27 17:02:07 +01:00

The issue with surface thickness and planes has been resolved in cda81d5a4d (#73866 had the same issue).
Closing since, in my view, this is no longer an issue.

The issue with surface thickness and planes has been resolved in cda81d5a4d39 (#73866 had the same issue). Closing since, in my view, this is no longer an issue.

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[Mantaflow] Particles not generated on Plane object #73161