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patriculus
01-13-2011, 06:32 AM
i have a simple doubt regarding Krakatoa....

i illuminated a scene with lots of particles with one spotlight....now i want to create Emissions for random particles....how can i do that...can i illuminate particles according to Particle Age

Bobo
01-13-2011, 07:33 AM
i have a simple doubt regarding Krakatoa....

i illuminated a scene with lots of particles with one spotlight....now i want to create Emissions for random particles....how can i do that...can i illuminate particles according to Particle Age

Yes, you can set any particle channel value of any particle based on any criteria.
To set the self-illumination channel of a particle, just follow the examples here
http://software.primefocusworld.com/software/support/krakatoa/magmaflow_fading_off_particle_density_by_age.php
but set the output as a Vector value to the Emission channel and make sure >Use Emission is checked in the Krakatoa Main Controls rollout.

In short, if your particles (for example coming from PFlow) have Age and LifeSpan channels, you convert the two from Integers to Floats, divide the Age by the LifeSpan and you end up with a floating point value between 0.0 at birth and 1.0 at death. You can now use this value to convert to a Vector (black and white) and output to Emission, or feed into the third slot of a Blend Operator with two input colors, or use the Vector value as TexuteCoord output and drive a GradientRamp for advanced emission effects etc. You can also apply this to random particles based on their ID or Index channel, or based on custom selections, or whatever you want.

Try it out and ask for help if you encounter problems...

patriculus
01-13-2011, 09:14 AM
thank you for the reply Bobo...i have one more doubt....here in this screenshot you can see the marked Events...can i restrict the illumination only to those events...i want the particles to illuminate only when they enter those events

http://img221.imageshack.us/img221/1747/45681843.jpg

attaching the scene file....

Bobo
01-13-2011, 04:45 PM
thank you for the reply Bobo...i have one more doubt....here in this screenshot you can see the marked Events...can i restrict the illumination only to those events...i want the particles to illuminate only when they enter those events

attaching the scene file....

What you could do is use a PFlow Mapping operator in the events to write a custom vector to any UVW channel (say, channel 2). Add a Mapping operator with the desired Emission color in the marked events, and another Mapping operator with value of 0,0,0 in all other events. Then just use a Global KCM if you are rendering the PFlow directly or a local KCM on the PRT Loader if you are rendering from disk that copies UVW channel 2 into the Emission channel. This way, the PFlow itself will provide the Emission data, on a per-event basis!

patriculus
01-13-2011, 05:36 PM
am really a newbie to KCM...just started using a few days ago...if u have time can u please make those changes in that scene and reupload....i can then download it and learn it...

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