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Primitive Color via Chops?

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markerline
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I have included a hip file that has a sphere which animates its primitive colors according to $F (frame) .

I would like to animate according to CHOPS manipulation. So I could possibly drive the color of the surface primitives by a music file or an envelope or noise or anything else in CHOPS.

I don't really know how to use VEX so please keep the help simple and to the basics.

Thanks in advance for any help.

Sincerely,
markerline

Attachments:
primitive_color_temp.hip (147.1 KB)

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tamte
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the key is to ensure that points generated from primitives are in the same order
then for transfering the color back to primitives you can use Primitive SOP and it's second input to get the color from corresponding points

Attachments:
primitive_color_temp_fix.hip (78.5 KB)

Tomas Slancik
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Method Studios, NY
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markerline
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Thanks. I will respond to your file in a moment once I open it but I wanted to say I saw a vimeo tut by Peter Quint on CHOPS and particle colors. However since I'm using Primitive Colors I can't seem to get the Primitive ID the way he got the Particle ID to change colors individually. It seems his method applies a change in color to the sphere as a whole. I'm sure your method addresses this. Here is his video link:

http://vimeo.com/6931106 [vimeo.com]
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markerline
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Thanks for that file. I seemed to be able to do some extra manips in CHOPS to get results somewhat to what I want. Since the vertex order is in sequence I get a spectrum rainbow.

What if I want a random array of colors across the sphere?
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tamte
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the continuous rainbow is not because of the order but because you are getting positions from points(primitive centers) and using that as a source to the color then just adding the same temporal noise to each component of each color therefore just uniformly offsetting that rainbow color distribution

if you want purely random variating colors, then either generate it before taking to chops , then process
or
generate unique noise curves directly in chops (see example)

but it's really about what you are aiming for

Attachments:
primitive_color_chops_random.hip (77.4 KB)

Tomas Slancik
FX Supervisor
Method Studios, NY
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markerline
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hey, that's a pretty neat expression or channel naming in the noise function. I've known to use $OS for group names but this is pretty unique and I've never seen it done that way. Houdini is limitless.
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