Hy All,

I am new to this forum, and also quite fresh with Houdini.

I have a probably trivial problem that I am facing at the moment with Houdini.

We are working on a school project, where we want to apply a reverse dissolve effect on a random object. I am working on different versions right now… as always I started up with research for references, when I came across this:
https://vimeo.com/76375296 [vimeo.com]

this is pretty much what I would like to recreate.

My approach was, to take it apart, how I could have been made. First of all I thought there is eighter a bounding box controlling/triggering the animation what happens on different polygons and different scale, or somehow with some CHOP magic.

Due to the lack of my knowlegde of advanced usage of CHOP, I went with the first one, so I created an animated bounding box coloring my object red. I am measuring the distance between the point and my bounding box, so my red color is gradient, this way I should be able to trigger an animation when the avarage color of the polygon is above a certain amount.

Well, I am attaching where I got stuck, please help me if you have an idea.

Regards,
Kornel

The PolyExtrude SOP is run per polygon, not per point. You need to have your attribute (color) as a primitive attribute, not point attribute - then you can use it directly on your polyextrude parameters.

Here I added an AttributePromote SOP to convert your point color to primitive color, and changed the expression on your PolyExtrude SOP to just “$CR”. (note that the values from your distance expression are not clamped to )

Thank you very much, it was a good lesson!, and I can see that I might have a chance to acomplish my plan.. After clamping the values, it already looks like its getting there, but I assume there must be better solutions for this.. I guess it comes later as I advance in Houdini.

Kornél Varga
After clamping the values, it already looks like its getting there, but I assume there must be better solutions for this.. I guess it comes later as I advance in Houdini.

Here are a couple of additional ways of doing this, one is by transferring attributes from one mesh to another, the other by testing whether a primitive is inside another mesh or not.