[Radiance-general] another water question

[Rob Guglielmetti]

Gregory J. Ward wrote:

> You probably want to add a time-dependent wave texture to your  
> water's surface as well, since most of what makes a person difficult  
> to see while underwater is the reflections off the surface, which are  
> constantly in motion.  I recommend doing an animation for that reason.

Thanks Greg for the excellent tips on modeling water, but I'm afraid you 
have opened up another can of worms with the last paragraph, above.  You 
mention a time-dependent wave texture. (!)  This sounds rather like some 
sort of variable texture that modulates the surface normal based on a 
time input.  One could script up a run of images and for each frame that 
water material would be modified by a random deformation that is keyed 
to timestep?  This sounds like an interesting application, and I was 
wondering if you had a framework for such a material description.  cal 
files are really something I'm trying to understand more, and each 
example helps a little bit more. 

- Rob