I wish to create a shadow for an animated particle system. Since it is an animated particle system with 25 frames per second the way to do this described here, is not possible (or at least not if you wish to finish the animation within five years).
Does anybody know a solution for this problem in blender 2.34?
from or on?
well, either way you could use dupliverted meshes [plane? cube? whatever] instead of halos and you could even use ray shadows [but they would be really slow
I have a method that I use, but it only works for the internal renderer.
In the internal renderer an object with an alpha value of 0.001 is invisible but since alpha is not 0 it casts a full shadow.
So I render one animation with the particles dupliframed with some object of the appropriate size and an alpha of 0.001 which will be the scene with shadows.
Then make an animation of only your particle system and combine the two in the sequence editor.
Alternatively you could duplicate your particle emittor and set one to be dupliframed with the objects and render in one pass.
GreyBeard
In the internal renderer an object with an alpha value of 0.001 is invisible but since alpha is not 0 it casts a full shadow.
Well, that’s OK, but if you want to do the same you can use a material with ENV activated. This will render the object “alpha only” but still casting shadow.
I think you can also use an Environment Map to simulate halos shadows.
Cheers.
malefico,
But then your background shows through
Blue is the world color. Box has env on. Floor does not. I don’t think this works for what he wants. with the box set at alpha .001 you get
Perhaps there is something I’m missing because a solution that works with yafray would be nice?
GreyBeard
Yes you’re right. I forgot that. This works for masking in order to render separately (rendering without the sky with Premul/Key options). For particle shadows it won’t work. My mistake 
Anyway, I think using the technique described in the tutorial for STATIC particle systems is not that hard for an animation. You only need to convert an image sequence (for instance using XnView) and make an animated texture with it.
Or using an Environment Map with proper coordinates and mapping for the particle system and using it as shadows instead of reflection. If i had the time I would make an example.
Cheers.
malefico.-
EDITED: Well, seyacat has written a tutorial on this technique you can find it at http://www.seyanim.com/tutos/envmapshadow.htm (in spanish, sorry, but maybe you can grasp the idea from the images)
