Weird bug with Particle Instance Modifier #53341

New Issue

Steffen Dünner · 2017-11-18T01:27:14+01:00

Steffen Dünner commented

2017-11-18 01:27:14 +01:00

System Information
Win 10 x64, nVidia GTX 1080Ti

Blender Version
Broken: All
Worked: (optional)

Short description of error
I have a very weird bug with the Particle Instance Modifier. In the OpenGL viewport, rendered view and when rendering in the GUI (F12) everything renders fine, but when rendering via command line or on the farm (with cgru, i.e. a farm software rendering with the command line), the instances are located at the wrong place.

I use a very simple hair emitter to instance meshes along the strands using the "Create along Paths" option. It works very nicely and interactively in the viewport but fails in a very weird way as soon as I send my scene on the farm. I attached a simplified version of the scene and hope it can be fixed.

Exact steps for others to reproduce the error

Load this blend file:
Instance_Bug_v01.blend
Press F12 to render. It looks like this:
Now call the same render via command line. It should work like this, you will have to change the paths:

blender -b "E:\Instance_Bug_v01.blend" -o "E:\Instance_Bug.#" -s 1 -e 1 -a"

This is the result:
All the instances now start from the origin of the scene (at least in this example). And they also have weird velocity vectors.

P.S.: Here are the motion vectors when rendering with the command line. There is no animation or deformation on these instances whatsoever, when rendering in the GUI the motion vector pass is totally neutral / empty:

**System Information** Win 10 x64, nVidia GTX 1080Ti **Blender Version** Broken: All Worked: (optional) **Short description of error** I have a very weird bug with the Particle Instance Modifier. In the OpenGL viewport, rendered view and when rendering in the GUI (F12) everything renders fine, but when rendering via command line or on the farm (with cgru, i.e. a farm software rendering with the command line), the instances are located at the wrong place. I use a very simple hair emitter to instance meshes along the strands using the "Create along Paths" option. It works very nicely and interactively in the viewport but fails in a very weird way as soon as I send my scene on the farm. I attached a simplified version of the scene and hope it can be fixed. **Exact steps for others to reproduce the error** - Load this blend file: [Instance_Bug_v01.blend](https://archive.blender.org/developer/F1152493/Instance_Bug_v01.blend) - Press F12 to render. It looks like this: ![GUI.png](https://archive.blender.org/developer/F1152494/GUI.png) - Now call the same render via command line. It should work like this, you will have to change the paths: ``` blender -b "E:\Instance_Bug_v01.blend" -o "E:\Instance_Bug.#" -s 1 -e 1 -a" ``` - This is the result: ![Batch.png](https://archive.blender.org/developer/F1152500/Batch.png) - All the instances now start from the origin of the scene (at least in this example). And they also have weird velocity vectors. P.S.: Here are the motion vectors when rendering with the command line. There is no animation or deformation on these instances whatsoever, when rendering in the GUI the motion vector pass is totally neutral / empty: ![MVecs.png](https://archive.blender.org/developer/F1152549/MVecs.png)

Steffen Dünner commented

2017-11-18 01:27:14 +01:00

Changed status to: 'Open'

Steffen Dünner commented

2017-11-18 01:27:15 +01:00

Added subscriber: @SteffenD

Bastien Montagne commented

2017-11-20 10:35:15 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2017-11-20 10:35:15 +01:00

Found two other bugs already while trying to confirm yours… :/

Steffen Dünner commented

2017-11-20 11:20:37 +01:00

Thanks, I actually had render crashes in this project, but it was too weird to reproduce easily. Also I am currently too swamped with work. Hopefully you can kill all these bugs ;)

Sebastian Parborg commented

2019-02-05 13:33:30 +01:00

Added subscriber: @ZedDB

Sergey Sharybin was assigned by Sebastian Parborg

2019-02-05 13:33:30 +01:00

Sebastian Parborg commented

2019-02-05 13:33:30 +01:00

This seems to still be a problem with the latest blender 2.8 beta.

Sergey Sharybin commented

2019-02-06 16:25:47 +01:00

@ZedDB, i can not reproduce the issue here, but i can currently only render on CPU. Does it happen when file is re-saved with CPU settings for you?

Sebastian Parborg commented

2019-02-06 20:07:11 +01:00

@Sergey it seem like it can not longer reproduce the issue on my end with either blender 2.8 or blender 2.79 :S

I don't know how I managed to reproduce this yesterday...
Should we just mark this as resolved?

@Sergey it seem like it can not longer reproduce the issue on my end with either blender 2.8 or blender 2.79 :S I don't know how I managed to reproduce this yesterday... Should we just mark this as resolved?

Sergey Sharybin commented

2019-02-06 21:23:45 +01:00

@SteffenD, do you mind testing latest build from builder.blender.org?

Steffen Dünner commented

2019-02-07 00:06:00 +01:00

In #53341#614867, @Sergey wrote:
@SteffenD, do you mind testing latest build from builder.blender.org?

I just did (actually I tried an own build of the very latest 2.7 on Linux Mint) and the result is still the very same as back then.
Here is what it looks like:

> In #53341#614867, @Sergey wrote: > @SteffenD, do you mind testing latest build from builder.blender.org? I just did (actually I tried an own build of the very latest 2.7 on Linux Mint) and the result is still the very same as back then. Here is what it looks like: ![Instance_Bug.1.png](https://archive.blender.org/developer/F6532429/Instance_Bug.1.png)

Sebastian Parborg commented

2019-02-07 00:21:51 +01:00

@SteffenD can you try 2.8 also?