point vop gradient

[herr.ja]

Helou houdini's folks!

Just a superquick question. I am trying to define @Cd attribute, by distance from certain group of points. I am using pig head volume filled with points, and unfortunatelly I dont know, how to create black and white gradient, based on distance of selected group of inner points and outer points (explained in the attached picture). Can you guys help me out, please?

(And additional question: is it possible to define it all at vop without selecting group of inner points previously?)

 

I will be very thankful for any advces. 

 

 

Cd_distance.hipnc

Edited March 22, 2023 by pan.mentolka

[Ziyad]

Hi mate

One approach would be to isolate the inside group and then use them in a nearpoint function to get the distance between them and outer points, so a bit similar to your original thought. If you want to avoid groups and just get gradient by distance to center of volume, you can extract the centroid of your volume as a point and use that in the same nearpoint setup. I've adjusted your hipfile here to show both approaches, hope this helps! 

 

 Cd_distance.hipnc

[animatrix]

Hi,

If you have a VDB SDF, you can use it to do distance lookups using the volumesample function and set the gradient according to some signed distance range, i.e. -1 to 1, etc. 

[herr.ja]

Thanks guys! Both of you, I used Ziyads method. It was exactly what i was looking for

Edited March 26, 2023 by pan.mentolka