I've got a mesh with velocity data, imported from abc. Now, I'd really love to color the mesh using a ramp based on velocity data. As I am not very proficient in Shops, I was wondering, how to do that.

I found a GetAttribute Node, but that wants some external bgeo to read the Attribute from. I was thinking about converting the ABC to BGEO, but I do not see much sense in doing so.

I thought there must be another, very simple way to read Velocity, pipe that into a ramp which then controls the diffuse color.

Is there a simple example anywhere around where I can see how this is basically done?

If you're just looking for a viewport solution, you can turn on “Override Color Attribute” and enter “v” in the field, in the Display Options > Geometry tab. There are a couple of pregenerated ramps you can apply to the result.

Thank you very much, bit I was also looking for a way to render it in mantra.

You can use vopsop and just connect the velocity input to the color output.

I think you might be looking for this.

Make sure your shader has the “use point color” checkbox ticked.
This will make your shader pick up the Cd (color) attribute.

Dear Mawi,

I've been trying to use your provided file and it won't work with my geo. It is not particles, it is lots of RBD point objects instancing cubes but I don't understand why its not working as they all have velocity attrs on their points like your example file.

Yours curious,

5DN.

Instancing doesn't automatically propagate point attributes to the instanced objects. Here's a solution via material overrides - there are other ways too, I'm sure

cheers eetu

eetu
Instancing doesn't automatically propagate point attributes to the instanced objects. Here's a solution via material overrides - there are other ways too, I'm sure

Turns out I wasn't instancing, but using a RBD point object. Sorry for the bad Houdini vocab.

I have attached my hip. Dunno whats going on.

don't forget to normalize the velocity before, you might need to find the max and min values of the frame range.