Children particles hair interpolation not correct with textures or dp #51774

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opened 2017-06-11 16:16:55 +02:00 by Thomas Beck · 7 comments
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System Information
Ubuntu Gnome 17.04, 2xGTX1070, i7 4th gen

Blender Version
Broken: all versions starting from 2.74
Worked: All versions <= 2.73a

Short description of error
Children hair particles interpolate between each other even when there should be no particle hair between them.

For a client's project we needed to have a particle system distribute hairs all over the place. We used children particles with the "interpolate" mode for that and drove the distribution of the particles with a b/w texture. The problem is that not only the white parts of the texture become populated with hairs but even the black ones once you set the children interpolation mode to simple or interpolated. This should not happen and didn't happen with 2.73a . So I assume that this is a regression that no one noticed since now.

Exact steps for others to reproduce the error
ParticleInterpolation.blend
Look at the supplied file in current master and in 2.73a or minor. Change the children interpolation mode to none to see where the texture is creating particles, then set it to simple or interpolated.

Notice:

  • The height of the hair particles is decreases when you increase the steps in the display panel (viewport) or render panel (rendering) ...
  • Dynamic Paint has the same problems: "zero weighted" vertices still cause hair interpolations in newer Blender versions...

How it should be (& was in 2.73a): Interpolation_2.73_side.png
How it is now: Interpolation_2.79_side.png

Greetings,
Thomas

**System Information** Ubuntu Gnome 17.04, 2xGTX1070, i7 4th gen **Blender Version** Broken: all versions starting from 2.74 Worked: All versions <= 2.73a **Short description of error** Children hair particles interpolate between each other even when there should be no particle hair between them. For a client's project we needed to have a particle system distribute hairs all over the place. We used children particles with the "interpolate" mode for that and drove the distribution of the particles with a b/w texture. The problem is that not only the white parts of the texture become populated with hairs but even the black ones once you set the children interpolation mode to simple or interpolated. This should not happen and didn't happen with 2.73a . So I assume that this is a regression that no one noticed since now. **Exact steps for others to reproduce the error** [ParticleInterpolation.blend](https://archive.blender.org/developer/F627558/ParticleInterpolation.blend) Look at the supplied file in current master and in 2.73a or minor. Change the children interpolation mode to none to see where the texture is creating particles, then set it to simple or interpolated. Notice: - The height of the hair particles is decreases when you increase the steps in the display panel (viewport) or render panel (rendering) ... - Dynamic Paint has the same problems: "zero weighted" vertices still cause hair interpolations in newer Blender versions... How it should be (& was in 2.73a): ![Interpolation_2.73_side.png](https://archive.blender.org/developer/F627553/Interpolation_2.73_side.png) How it is now: ![Interpolation_2.79_side.png](https://archive.blender.org/developer/F627555/Interpolation_2.79_side.png) Greetings, Thomas
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Changed status to: 'Open'

Changed status to: 'Open'
Author
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Added subscriber: @plasmasolutions

Added subscriber: @plasmasolutions
Bastien Montagne was assigned by Thomas Beck 2017-06-11 16:24:23 +02:00

Added subscriber: @zeauro

Added subscriber: @zeauro

It looks like a problem relative to steps.
If you increase steps number in Display panel to 10 ; paths of children with a null length are reduced to points.

2.74 introduces gooseberry changes. I am not surprised that such regression about children came after these changes.

It looks like a problem relative to steps. If you increase steps number in Display panel to 10 ; paths of children with a null length are reduced to points. 2.74 introduces gooseberry changes. I am not surprised that such regression about children came after these changes.
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@zeauro Look at what I wrote under "Notice" - can confirm that.

@zeauro Look at what I wrote under "Notice" - can confirm that.

This issue was referenced by 3190eaf109

This issue was referenced by 3190eaf10942c2ce9e5102f209902c8bad674fe9

Changed status from 'Open' to: 'Resolved'

Changed status from 'Open' to: 'Resolved'
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Reference: blender/blender#51774
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