Particle trails not working #65542

New Issue

Salai Vedha Viradhan · 2019-06-05T21:48:36+02:00

2019-06-05 21:48:36 +02:00

System Information
Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64

Blender Version
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-06-05 13:55, hash: 806d4fbc5e
Worked: (optional)

Short description of error
Particle trails are not working in the latest build of Blender 2.8.

If I copy the same object into Blender 2.79, everything is working perfectly.

I think recently the particle system got a patch for better handling of multiple threads and large simulations. May be, some issue with that. @juang3d

I have attached the blend file. particle_trails_not_working.blend (Blender 2.8)

Exact steps for others to reproduce the error
Just add a particle system to the default cube and try increasing the trail count.

**System Information** Operating system: Windows-10-10.0.17763 64 Bits Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64 **Blender Version** Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-06-05 13:55, hash: `806d4fbc5e` Worked: (optional) **Short description of error** Particle trails are not working in the latest build of Blender 2.8. If I copy the same object into Blender 2.79, everything is working perfectly. I think recently the particle system got a patch for better handling of multiple threads and large simulations. May be, some issue with that. @juang3d I have attached the blend file. [particle_trails_not_working.blend](https://archive.blender.org/developer/F7088697/particle_trails_not_working.blend) (Blender 2.8) **Exact steps for others to reproduce the error** Just add a particle system to the default cube and try increasing the trail count.

Salai Vedha Viradhan commented

2019-06-05 21:48:36 +02:00

Added subscriber: @salaivv

Salai Vedha Viradhan commented

2019-06-05 22:20:51 +02:00

Added subscriber: @juang3d

Jacques Lucke commented

2019-06-06 12:46:43 +02:00

Added subscribers: @brecht, @JacquesLucke

Jacques Lucke commented

2019-06-06 12:46:43 +02:00

Did particle trails ever work in Blender 2.8? It looks like no code actually uses the trail_count variable currently.

Was it removed as part of 51b796ff15?

@brecht, Since the option is doing absolutely nothing right now, we can also remove it?

Did particle trails ever work in Blender 2.8? It looks like no code actually uses the `trail_count` variable currently. Was it removed as part of 51b796ff15? @brecht, Since the option is doing absolutely nothing right now, we can also remove it?

Brecht Van Lommel commented

2019-06-06 12:52:21 +02:00

Remove it. It was never supported in Cycles or Eevee, and I would consider adding it there a feature rather than a bugfix.

Salai Vedha Viradhan commented

2019-06-06 13:09:08 +02:00

@brecht @JacquesLucke

But, the default render mode 'halo' is also not supported by Cycles/EEVEE. Anyway invariably we will have to add an object or collection to render the particles. Does it really have to be removed?

I was basically create a few vegetation assets. So, I was just using the trails as a visual aid. Because, otherwise we will have to bake the particles to actually see their path. I found using trails was more interactive and I could finally bake and convert the paths to editable geometry when I am happy with the simulation.

Can it stay just as a visual aid?

@brecht @JacquesLucke But, the default render mode 'halo' is also not supported by Cycles/EEVEE. Anyway invariably we will have to add an object or collection to render the particles. Does it really have to be removed? I was basically create a few vegetation assets. So, I was just using the trails as a visual aid. Because, otherwise we will have to bake the particles to actually see their path. I found using trails was more interactive and I could finally bake and convert the paths to editable geometry when I am happy with the simulation. ![trails.JPG](https://archive.blender.org/developer/F7089959/trails.JPG) ![002.jpg](https://archive.blender.org/developer/F7089960/002.jpg) Can it stay just as a visual aid?

Brecht Van Lommel commented

2019-06-06 13:14:41 +02:00

There is nothing against adding support for it in the new viewport, but it would not be handled as a bugfix. Until that happens, options that do nothing should be removed.

Jacques Lucke commented

2019-06-06 13:54:47 +02:00

Turns out there are a lot of options that don't seem to do anything anymore. Almost none of the flags in eParticleDrawFlag is used. But all the options are in the UI still.
I suggest for Blender 2.80 we just remove the python part of these options instead of removing the C code.
If necessary, the C code can be cut out later, or we wait with that until we can remove the entire particle code.

Turns out there are a lot of options that don't seem to do anything anymore. Almost none of the flags in `eParticleDrawFlag` is used. But all the options are in the UI still. I suggest for Blender 2.80 we just remove the python part of these options instead of removing the C code. If necessary, the C code can be cut out later, or we wait with that until we can remove the entire particle code.

Brecht Van Lommel commented

2019-06-06 14:15:30 +02:00

In #65542#696251, @JacquesLucke wrote:
I suggest for Blender 2.80 we just remove the python part of these options instead of removing the C code.
If necessary, the C code can be cut out later, or we wait with that until we can remove the entire particle code.

Agreed.

> In #65542#696251, @JacquesLucke wrote: > I suggest for Blender 2.80 we just remove the python part of these options instead of removing the C code. > If necessary, the C code can be cut out later, or we wait with that until we can remove the entire particle code. Agreed.

Jacques Lucke self-assigned this 2019-06-06 14:24:59 +02:00

Jacques Lucke commented

2019-06-06 15:59:39 +02:00

Changed status from 'Open' to: 'Resolved'

Jacques Lucke closed this issue

2019-06-06 15:59:39 +02:00

Jacques Lucke commented

2019-06-06 15:59:39 +02:00

Particle trails are not supported currently. The settings for it are not in the ui anymore: 87fde57b63

Particle trails are not supported currently. The settings for it are not in the ui anymore: 87fde57b63

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Particle trails not working #65542