web.46894aed94b24855869b4c780@news.povray.org...

> 1) Ambient occlusion is so specific that you can almost say it has only 
> one
> or two uses. It's not flexible. I might never use it very much. Can't
> really say the same about radiosity, which I use a lot.

In my experience, AO can be used in a stand alone fashion as a replacement 
for radiosity and it can actually be good enough in some circumstances, but 
usually it's too unrealistic and can have bizarre side effects. As you said, 
it is very specific.

However, I find AO to be extremely handy and it would be a welcome addition 
to the POV-Ray toolset. Particularly, AO is extremely useful when used with 
radiosity. Typically, radiosity requires high sampling values to get 
detailed shadows in corners: it's hard to fine tune and can be very slow 
and/or memory consuming. When AO and radiosity are used together, AO can 
work its magic in the corners so that it becomes possible to lower the 
radiosity sampling = faster rendering. For instance, FinalRender has AO both 
as a standalone shader and as a part of its GI system, where it's used as an 
add-on to increase GI quality.

AO can be also used to create interesting texture effects, provided it can 
be set per object with the abiliy to drive other 
textures/materials/channels/shaders. One obvious use is cheap patinas. 
Another creative use I've seen was the following : to create a fuzzy darker 
stain on a surface without the hassle of defining a new texture layer or 
editing a bitmap, just create a new polygon object of the desired shape, 
make it invisible to anything but AO, and make it float above the surface to 
generate the stain...

G.

Post a reply to this message