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View Full Version : convert particle collisions U and V to 3D coordinates


misterwolfy
11-19-2010, 01:07 PM
I have a collision event that produces collision U and V output.


float $colU = particleShape1.collisionU;
float $colV = particleShape1.collisionV;


I get results like:

collisions in u: 0.9518819253 collisions in v: 0.6064704928
collisions in u: 0.9414537137 collisions in v: 0.6129580163
collisions in u: 0.619097031 collisions in v: 0.7295783004

How do I convert these UV coordinates to spacial coordinates? I want Z X so that I can place objects at the points of collision.

the collision is between a 2x2 plane emitting particles and a 2x2 plane that they are colliding with.

Thanks for reading!!

misterwolfy
11-19-2010, 01:11 PM
My solutions did not wor so far, maybe there is a way?


http://www.youtube.com/watch?v=1ZDQdrswyHc (http://www.youtube.com/watch?v=1ZDQdrswyHc)


float $colU = particleShape1.collisionU;
float $colV = particleShape1.collisionV;

if ($colU > 0) {
particleShape1.lifespanPP=0;
print ( "collisions in u:" + $colU + "collisions in v:" + $colV+"\n");
setAttr "locator.translateX" ($colU*20);
setAttr "locator.translateZ" ($colV*10);
}

Jacobborsting
11-22-2010, 03:27 PM
could you upload your scene?

misterwolfy
11-22-2010, 03:40 PM
Sure, but I already figured it out, with some help form a cc user named Nowayfra. (http://www.creativecrash.com/forums/dynamics-amp-effects/topics/interpreting-the-position-of-a-particle-collision--2/posts/306216)

Here is the file (http://www.mrwolfy.com/uploads/particleCollisionTest.mb.zip), before I fixed it. Paste (replace) the code below into the only expression in the scene to repair. I commented the line that was giving me trouble below.


float $colU = particleShape1.collisionU;
float $colV = particleShape1.collisionV;
int $time = `currentTime -q`;

if ($colU > 0) {
particleShape1.lifespanPP=0;
setAttr "loc.translateX" ($colU*10);
//this is the line that was giving me trouble, values needed to be inverted.
setAttr "loc.translateZ" ((1 - $colV) * 10);
}



Thanks

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