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AOV and points in Mantra

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I'm trying to create the pass that would illuminate my character being affected by a "sphere of scattered points" nearby him. Such sphere has a lot of points.

What I'm doing at the moment is using a very simple vopshop which has an Incidence node inside, applied to the guy, and loading the baked particles which have a shader that reads Cd and applies it to Cf, but the resulting render is very slow and very very grainy, even when pushing up the samples.

Its been so long since I've been doing any shading or comping and I'm a little struggling and surely missing some new way of doing it with Mantra, any help would be very appreciated


I posted it on SidefX too as I'm a little bit in a rush, sorry for the double post! :)

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Well, as always, things pretty much depend on the larger context of your shot.

In general, I'd say having a different set of geometry for the visible surface of the particles and the one taking part in the lighting calculations should be a good idea.

I imagine that now most of your rays miss the particles, and that kind of on/off results for the rays are very disadvatageous for getting smooth results.

At least try making a "phantom" copy of your particles, with an increased the particle size or spheres copied to them or something.

Here's a couple of quick hips that might inspire something, 1 has a couple of different unseen geometries that light the object via radiosity, 2 uses them as geometry light.

For other things to try, you might try instancing point lights to your particles.



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oh thanks a lot .. I tried that approach and it worked much better for the light emitting sphere ... little trickier to set it up for the lightnings but seems like the quality is much better at least ...

thanks for the sample files!

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