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Particle system texture added via API not working ['blend_type' when created using the interface is MULTIPLY, whereas when created through API, its value is MIX]
Confirmed, LowPublicKNOWN ISSUE

Description

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.92

Blender Version
Broken: version: 2.83 (sub 17), branch: master, commit date: 2020-05-20 20:54, hash: rBaf3a55bb1b7d

Short description of error
Hi,

I have been trying to write a script that automatically adds a clouds texture to control the density of hair particles/instances. I have been able to successfully add a texture to the active particle system of the selected object with the Density checkbox under Influence activated -- all done through API. However, there is no effect on the density of the particles.

I am clueless of why this is happening. Is this a bug?

I have attached a blend file (with an internal script) for reproducing the bug.

Exact steps for others to reproduce the error

  • Open the attached blend file.
  • Allow execution of scripts (in case not allowed)
  • Select the plane (already has a particle system) and search for 'Particle Density Texture' and execute the script.

The texture will get added successfully to the particle system's texture slots with the density option on, but will have no effect on the particle distribution whatsoever. The script also has an UNDO panel. You could try changing values there or in the properties panel as well, but will have no effect.

Am I doing something wrong? Or is this a bug or a known issue or any API limitation?

Event Timeline

Philipp Oeser (lichtwerk) changed the subtype of this task from "Report" to "Known Issue".

Can confirm.

I would not hold my breath here though since the particle system is EOL and is to be replaced with particle nodes...

Germano Cavalcante (mano-wii) changed the task status from Needs Triage to Confirmed.May 22 2020, 3:20 PM
Germano Cavalcante (mano-wii) triaged this task as Low priority.

I was able to get it working finally. The issue was with the blend_type property of the particle system texture. When created using the interface its value is MULTIPLY, whereas when created through API, its value is MIX. Changing this in the script finally made it work.

Just out of curiosity, once the particle nodes land in Blender, everything like hair based instancing has to be done through nodes only?

Philipp Oeser (lichtwerk) renamed this task from Particle system texture added via API not working to Particle system texture added via API not working ['blend_type' when created using the interface is MULTIPLY, whereas when created through API, its value is MIX].Mon, Jun 22, 10:52 AM