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Basic Attribute Transfer Question


Steve Sloan

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I have an animated texture map that i want to use to birth particles on an obj sequence exported from maya. I can get the texture map to stick to the deforming geo with a rest sop - i just don't know how to transfer the texture map info onto the deforming geometry so i can birth particles from it. easy in maya and i'm sure even easier in houdini... right?

many thanks

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I have an animated texture map that i want to use to birth particles on an obj sequence exported from maya. I can get the texture map to stick to the deforming geo with a rest sop - i just don't know how to transfer the texture map info onto the deforming geometry so i can birth particles from it. easy in maya and i'm sure even easier in houdini... right?

many thanks

If I understood your question correctly - you should use 2 copies of your geometry - 1 not-deformed and 1 deformed. Apply whatever attributes you like to your not-deformed (initial) geometry and then simply attr-transfer\attr-copy your attributes on to the deforming (imported) sequence.

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all you need to is get one piece of your geometry sequence working. Just lock it on frame one.

get your texture and your shader to work on it. Now, all you have to do is take a pointSOP and input the deforming sequence of geometry into the second input and in the Transform channel put $TX2 $TY2 $TZ2. now if you do this and your topology is consistent over time the locked piece of geometry will now move to the position of the sequence over time. So you texture and shader will come along for a ride.

To birth the particles over time based on the image sequence you need to look up the image sequence over time. I'm not a POPs person so there might be a different way to do this, however, the easiest thing to do here is to use a pic expression in a pointSOP so the image sequenced colors points in your geometry over time (black and white) and the you can birth points based on that attribute...You can specify it as the Cd attribute.

I'm sure there is a pointSOP demo somewhere with the pic expression somewhere...

Just be aware that this method will leave you with only the level of detail in your geometry interior of polygons will just be an interp of the points comprising that polygon.

that should be enough to make you dangerous.

-k

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