Inherit Color From Particle Emitted

[christiangreet]

How can I get a Particle to inherit the color of the particle it has been emitted from?

[grymmeg]

You could use a expression.

First you have to add the dynamic attributes parentId and rgbPP to the child particle system.

Then the creation expression:

float $parentId=parentId;
vector $rgbPP=particle -attribute rgbPP -id $parentId -q particleShape1;
rgbPP=$rgbPP;
//particleShape1 is the name of the emitting parent particle system

And thats it.

/G

[joojaa]

well since thet uses mel inside a expression its a bit dangerous and perverst mayas runtime. Its actually better to do this in the emission event.

[grymmeg]

Yes, expressions takes a lot of CPU. This metod works mostly for me, but it can be a bit frustrating when it comes to weird errors, like when some particles never dies. I dont actually understand exactly what you mean with emission event. I know of collision event and the emit commando.

So if there is some other better way, I would love to know.

/G

[joojaa]

QUOTE(GrymmeG @ 01/25/09, 06:16 PM) [snapback]299600[/snapback]
Yes, expressions takes a lot of CPU.

Well no actually not, its just that CALLING:

particle -attribute rgbPP -id $parentId -q particleShape1;

inside a expression is HUGELY inefficient since it is NOT a expression. Also it contains a lot of stupid caveats for maya. Yes you can do that but yous hould avvoid doing it. As literary calling:

particle -attribute rgbPP -id $parentId -q particleShape1;

1 ime takes more time than to update 10,000 particles with proper dag evaluation order. Thius for 10,000 particles thats VERY slow as it makes for a very high exponential time drain.