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Evalia
08-07-2008, 12:06 AM
Hi !

I would like to control the particle emission on a polymesh with a light. more precisely I would like to control it according to the surface luminance. I tried to connect my shader to the particle lifespan (live in the shadow, die when brighter). I also tried to use the polymesh as a goal and connect the surface luminance to some goal attributes, but nothing seems to work !

Any Idea ? I stressed that I only have a basic MEL knowledge. Maybe there's a way to script that...?

Thanks for your help !

Aikiman
08-07-2008, 12:18 AM
This can be done all in the interface, woot! Make sure you add rgbPP to the particle shape (only needed if yoiu want to emit color also) Then in the emitter attributes down the bottom you'll find texture emission attrs. Pipe your texture in texture rate and enable texture rate. If you want them to emit from dark then enable that also.

Evalia
08-07-2008, 11:55 AM
I will try that !
thank you for your quick reply!!

azshall
08-07-2008, 06:12 PM
This can be done all in the interface, woot! Make sure you add rgbPP to the particle shape (only needed if yoiu want to emit color also) Then in the emitter attributes down the bottom you'll find texture emission attrs. Pipe your texture in texture rate and enable texture rate. If you want them to emit from dark then enable that also.

But reading his initial post, it sounds like he only wants this to happen where there is light hitting the surface?

Evalia
08-07-2008, 08:53 PM
Yes this is exactly what I want...
Actually I would like to control the particle emission with my shader (a simple luminance connected to a ramp B&W pluged in the ambient channel). So when I animate the light direction, it updates the ambient and the particles move accordingly...
I would like to avoid backing a map and controling the emission rate with this one...

thx. ;)

Aikiman
08-07-2008, 09:50 PM
doh! my bad sorry for not reading your post clearly...Ill have a look at the surface luminance node and see if that will give anything, BRB. One hack would be to animate a circular ramp but surely it can be done with luminance.

noxy
08-08-2008, 02:51 AM
It sounds like you need to bake the lighting and use that for emission.
Then you could even process it more to make sure you only get particles appearing where you want them.

At least that's what it sounds like you want.

-oops, just saw that you didn't want to bake, but that's the only way I could think of.

Jon

Evalia
08-10-2008, 02:58 PM
Thx everyone.
I think i will have to make up my mind to bake the map...


...

Aikiman
08-10-2008, 07:46 PM
Im unable to get the lumanance node to affect the texture rate sorry.

Evalia
08-10-2008, 09:31 PM
Thanks anyway...

;)

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08-10-2008, 09:31 PM
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