Le 04/06/2012 17:02, Sereib nous fit lire :
> Hello,
> 
> I work on a scene with an asteroid (isosurface) close to the earth (the
> atmosphere and clouds are two separate scattering media). Both, the asteroid and
> the clouds are very detailed, but render sufficiently fast if either the
> asteroid or (!) the clouds are part of the scene, or the asteroid does not cast
> its shadow over the clouds.
> 
> However, the rendering extremely slows down if the light source position moves
> and the shadow of the asteroid hits the clouds. I assume the combination of
> scattering media and isosurfaces casting their shadow on the scattering media
> causes lots of extra calculations ...
> 
> Adding "no_shadow" to the asteroid object is no option, this deteriorates the
> 3D-appearance of the asteroid.
> 
> I could also switch from "scattering" to "emission" for the cloud media, but
> this also looks less real.
> 
> Since the shadow on the clouds is almost invisible in this scene, it would be
> more than enough if - for calculating the shadow on the clouds - the asteroid is
> assumed to be just a sphere, or any other simple shape.
> 
> So it would be a great idea, to have a term like this:
> 
> object { ... shadow_lookslike{sphere{<x,y,z>,r}}}
> 
> which only holds for the calculation of shadows cast on any other object of the
> scene, not for the object itself. The shadow it casts over itself should not be
> affected.
> 
> I assume such a feature does not exist yet, what do you think about it?
> 
> Thank you in advance for your comments!
> 
> 

You should dive a bit in lightgroup and play with no_image. (for the
light source, cloud & sphere)
It might means a duplicated light source...

Post a reply to this message