>
> ...So I came upon the following idea: Instead of parsing and rendering
> the same objects over and over again, let's just do it once, capture
> the scene in an image file and use it as an image map on a z-plane.
> A bit like the scene in a theater. This basically works fine but
> the animated objects
> 1)  don't cast shadows,
> 2)  do not disappear behind the immobile objects.

And John Van Sickle wrote...

> See if you can replace the complex objects and their shadows with
> sprites.  Getting the projection math right is going to be non-trivial.

The idea of rendering one image of the scene and then projecting it onto simple
geometry is a very good one. Instead of a plane, though, it would probably look
better if projected onto  *multiple* simple objects, in space, to give the
resulting scene a more 3D appearance. Like multiple 3D 'billboards.' (Or
sprites?) The trouble with that is figuring out the necessary image scalings
that would need to be done to the overlaid image_map(s), to get the individual
'sizes' of the projected images to all be correct (that is, all the *same* size)
from the camera's point of view. Certainly not trivial!

A really unique and simple way of doing such a thing is to use an include file
for POV-Ray called "Illusion.inc", found here...

http://runevision.com/3d/include/

Essentially, it takes your single rendered image_map and projects it onto as
many objects in the scene as you like, while automatically scaling the image in
depth. I.e., so that a box at 500*z gets its piece of the image_map at the same
'projected size' as a box at 5*z. The overall result is that your animated
camera can move around (within limitations) and all the '3D billboards' will
still show their pieces of the image_map correctly-sized. As an additional
detail, you could have the image_map's 'point of projection' follow the camera's
position, always being projected from there. (I'm not even sure what that effect
would look like!--but it sounds intriguing ;-)  )

There are more details to this, of course, but the code might be worth checking
out.

I'm not sure if would solve your particular shadow problem, though.

BTW, I posted an animation to the newsgroups not too long ago, illustrating what
Illusion.inc does, in a basic way; it might be more easily-grasped than my
explanation here.

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