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!

Post a reply to this message