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I'm having a hard time setting up instancing in Solaris where I also use the color attribute in a material.

The setup is rather basic. I'm using the Instancer LOP to scatter the geometry. The points for the scatter are inside the Instancer LOP. Just double click on it. The important part of the points source is that I add color attribute to it which I try to use to drive the material in the shader per instance. Then I attach the material to the prototype. I had to create the several materials for both Octane and Karma to debug my issues. I use my color attribute for both Octane and Karma materials to drive the diffuse color. Only Karma works as expected when rendering and Octane doesn't. The weird thing with Octane is that if I cut the connection for the Color Vertex Attribute node then it works as expected by default. I don't think it's the expected behavior. Please, let me know if I'm doing something wrong and that's the reasons this workflow doesn't work for me in Octane and if there is an a better way to do this.

AlexeyAdamitsky wrote:I'm having a hard time setting up instancing in Solaris where I also use the color attribute in a material.

The setup is rather basic. I'm using the Instancer LOP to scatter the geometry.

20240515_houdinifx_mLNrbEWGdR.png

The points for the scatter are inside the Instancer LOP. Just double click on it. The important part of the points source is that I add color attribute to it which I try to use to drive the material in the shader per instance.

20240515_houdinifx_oaNBWAVS7t.png

Then I attach the material to the prototype. I had to create the several materials for both Octane and Karma to debug my issues.

20240515_houdinifx_RjmWnQSCQP.png

I use my color attribute for both Octane and Karma materials to drive the diffuse color.

20240515_houdinifx_7CXArzm8lt.png

20240515_houdinifx_7CXArzm8lt.png

Only Karma works as expected when rendering and Octane doesn't.

20240515_houdinifx_yeofv4fRpt.png

20240515_houdinifx_441Q9At0kb.png

The weird thing with Octane is that if I cut the connection for the Color Vertex Attribute node then it works as expected by default. I don't think it's the expected behavior.

20240515_houdinifx_bb6Qu0UZX3.png

Please, let me know if I'm doing something wrong and that's the reasons this workflow doesn't work for me in Octane and if there is an a better way to do this.

Hi Alexey,

Apology for the delayed response.

Its a bug and have reported it to our developer.
We will get it fixed asap!

cheers

You should use Texture Instance Color rather than Color Vertex Attribute. If there is no node attached to the material color, a Texture Instance Color is created automatically as a shortcut.

Phantom4 wrote:You should use Texture Instance Color rather than Color Vertex Attribute. If there is no node attached to the material color, a Texture Instance Color is created automatically as a shortcut.

Stuff like that really should be documented somewhere. Using a Texture Instance Color node is not enough because you also have to rename it to the attribute name. Unless there is some kind of documentation, how are we supposed to know this stuff?

Phantom4 wrote:You should use Texture Instance Color rather than Color Vertex Attribute. If there is no node attached to the material color, a Texture Instance Color is created automatically as a shortcut.

How to set CD in the Texture Instance Color node?

interelectronix wrote:

Phantom4 wrote:You should use Texture Instance Color rather than Color Vertex Attribute. If there is no node attached to the material color, a Texture Instance Color is created automatically as a shortcut.

How to set CD in the Texture Instance Color node?

Hi interelectronix,

Apology for the late response.
Have you tried with Octane ColorVertex and set the CD as *displayColor*?

In Solaris workflow, there are quite a few changes that we are also learning.
https://www.sidefx.com/docs/houdini/solaris/usd.html

Let us know if this works!!

cheers

Phantom4 wrote:You should use Texture Instance Color rather than Color Vertex Attribute. If there is no node attached to the material color, a Texture Instance Color is created automatically as a shortcut.

Hey, you need to set the name to displayColor for it to work, I had it working today like that.

Yeah the current workflow on this is a bit odd, but for instance attributes to work you have to drop down a instance texture node and RENAME THE NODE to the attribute you want it to read. So in most cases you would name it displayColor.
The vertex attribute node is used to read the color off geometry (actual points of your model) not the instances. Definitely aware that this is rather unintuitive and we're looking to improve this. Would be good to create some training content on this as well.