Let’s assume I have a scene with particles lit by light sources(s). I get a very nice internal shadows cast by particles onto particles.
Now I wonder if that’s possible at all to have these particles cast a shadow somehow onto a volumetric light effect to obtain godrays and partial volume light blocking.
I know it is possible with filling entire space with pVolume and rendering in krakatoa, but it is virtually impossible taking into account the amount of processing required for this.
I saw documentation about casting shadows by geometry and onto geometry, but I think it does not cover the above.
Atmospheric effects in Max are currently simply drawn on top of each other in the order of the effects list.
There is a solution from Sitni Sati / Afterworks called FusionWorks that allows Max atmospherics to blend together: afterworks.com/fumefx/FusionWorks.asp?ID=15
The Krakatoa Atmospheric effect currently does NOT support FusionWorks, but it might be a good idea to look into that. That being said, you would be forced to use the Krakatoa Atmospheric effect with Scanline or VRay which is not exactly the same as particle rendering in Krakatoa and would be significantly slower.
In Krakatoa SR and Krakatoa MY, we have added Pixar DTex support (for deep shadow maps and camera mattes) and we might port that to Krakatoa MX eventually. In that scope, we might be able to produce deep shadows to be passed to a volumetric light in Scanline/VRay to produce correct occlusion, but I am not 100% sure it would work - in general we store shadow data from geometry, not from particles. We also have plans to support some form of Deep Compositing (OpenEXR 2.0 output) in the future, that might be useful in some form to achieve what you want. But right now it is not supported.
A crude workaround would be to generate a mesh from the particles (e.g. using Frost or PFlow) and occlude the volumetric light with it. But still the compositing of the volume light rendering and the Krakatoa particle rendering will be tricky…
Thanks for your replies. I never worked with frost, but maybe I could try. Not sure though it if would manage with my geometry.
However, I can try to surface it in other kinds of software and use a low detail proxy for occlusion. Or just model something simple from scratch in Max to simulate the effect - probably a faster method.
