In article <3f871c85@news.povray.org>,
 "Hughes, B." <omn### [at] charternet> wrote:

> Well, I was about to go ahead and take it for granted that this is true. I
> just had to see it for myself. I didn't find any shadows from other light
> sources, whether the looks_like object is semi-transparent or opaque.

Hmm, that makes it pretty useless...apparently no different than a union 
of a light source and a shadowless object.


> Also, only has self-shadowing on a per primitive basis too. In a 
> union of sphere and cone, for example, each doesn't cast a shadow 
> onto  the other.

I'm not sure if you're describing what it does or what it should 
do...are you saying look_like objects cast shadows on themselves but not 
on other objects?

Unions are kind of tricky...they are internally split up into separate 
objects to make bounding more efficient. Manually bounding the union 
will disable this behavior unless the split unions option 
(Split_Unions=on or +SU for non-Mac versions) is turned on, in which 
case even bounded unions will be split. This burned me when I was 
experimenting with the proximity and curvature patterns...I have no idea 
how it interacts with looks_like, I'd need to take a close look at the 
code.

Anyway, I'd suggest you just use a union of the light source with the 
object representing the light. This gives you most control over what 
actually happens...you can make specific parts shadowless, etc. If we're 
going to talk about what looks_like *should* do, I think it should 
behave in exactly the same way as a union with the light source, but 
changing it at this point would probably cause more problems than it 
solves.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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