Hi everyone,

I’m trying to create a moving light strip / chasing or scanning effect in Houdini.

The effect I’m trying to achieve is similar to an LED strip where:

The entire strip remains constantly bright/emissive.
A moving section of light travels along the strip/path.
The moving section has a different color and/or higher emission intensity than the rest of the strip.
The moving section should produce a Glow/Bloom effect.
The bright section continuously moves/chases along the path.

I have been trying to achieve this using an emissive material on a path/strip, along with Glow, and I have set up a different color/emission for the moving section.

However, my current setup is not working as expected, and I’m not seeing the emissive effect in the final render.

I have attached/enclosed my Houdini setup file

I’m specifically sharing the file because I would really appreciate it if someone could look through my existing setup and point out what I have done incorrectly.

What is wrong or missing in my current node setup?

Why is the emissive material not appearing in the render?

Is my moving light mask/attribute being generated correctly?

Is the emission being transferred/applied correctly to the geometry?

Is there an issue with the material, render settings, or Glow/Bloom setup?

If there are mistakes in my current approach, I would really appreciate an explanation of what the mistake is and how I can fix it.

if there is another/better approach that can achieve the same visual result, I would also be very happy to learn about it.

Any help in reviewing the attached file and explaining where I’m going wrong would be greatly appreciated.

Hello! In your shader, import displayColor rather than Cd. This is the USD standard name, and any Cd attribute in sop is converted to displayColor primvars on import.

Also switch your geometry light's Material Sync Mode to "Material Glow Tints Light".

Tanto
Tanto

Thank you so much, Tanto! Really appreciate the help and the clear explanation. You saved me a lot of time and frustration with this.