i was thinking about making a real projection.  is there a way of giving a
ray of like composition? like for example, in a smoky room, it you turn on a
projector, and place a design on it, you will se the projector's ray
breaking up into parts.  is there a way of doing this pov-ray? or should i
just place a semi-transparant plane with a design on it in front of te
light-source?  but this seems to be taking too long in computing all the
photons

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I think you're asking if a pattern could go into 'media' in place of a light shone
through a semitransparent
image and onward into the media.
Well, maybe so.  A radial pattern could do that in a way but you would also need
multiple instances of that
pattern to get better 3D.  And it would still be media, which translates to slow
anyway.
I'm sure there would be other ways to fake it using only transparent to
semitransparent cones for example, but
considering that you probably will need the media filling the room anyhow then the
image projection method
could be the choice above all else.
Someone else might chime in here also with a thing or two on this.

Bob

"DreyWerx" <you### [at] hotmailcom> wrote in message
news:3a1aa74d$1@news.povray.org...
> i was thinking about making a real projection.  is there a way of giving a
> ray of like composition? like for example, in a smoky room, it you turn on a
> projector, and place a design on it, you will se the projector's ray
> breaking up into parts.  is there a way of doing this pov-ray? or should i
> just place a semi-transparant plane with a design on it in front of te
> light-source?  but this seems to be taking too long in computing all the
> photons

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In article <3a1aa74d$1@news.povray.org>, "DreyWerx" 
<you### [at] hotmailcom> wrote:

> i was thinking about making a real projection.  is there a way of 
> giving a ray of like composition? like for example, in a smoky room, 
> it you turn on a projector, and place a design on it, you will se the 
> projector's ray breaking up into parts.  is there a way of doing this 
> pov-ray? or should i just place a semi-transparant plane with a 
> design on it in front of te light-source?  but this seems to be 
> taking too long in computing all the photons

Shining the light through something is currently the only way to color 
the light. However, you only need photons for this if your light is 
being reflected or refracted in this scene.
About the photon calculation, it sounds like you just put a plane object 
in front of the light. MegaPOV will fire photons at the whole object, 
since planes are infinite, you will get a lot of photons fired at 
portions of the object that won't effect the results, and a lot fired 
into space. Try a 0-thickness box instead, or triangles or a polygon.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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I've done this before. I put a thin box in front of a spot light and put a
semi-transparant image map on it. Then, I placed an other box in front. This
gave me a large stick figure in a round light.
______
David McCabe
dav### [at] maccom
http://homepage.mac.com/davidmccabe/index.htm
God is good! 

>> i was thinking about making a real projection.  is there a way of
>> giving a ray of like composition? like for example, in a smoky room,
>> it you turn on a projector, and place a design on it, you will se the
>> projector's ray breaking up into parts.  is there a way of doing this
>> pov-ray? or should i just place a semi-transparant plane with a
>> design on it in front of te light-source?  but this seems to be
>> taking too long in computing all the photons
> 
> Shining the light through something is currently the only way to color
> the light. However, you only need photons for this if your light is
> being reflected or refracted in this scene.
> About the photon calculation, it sounds like you just put a plane object
> in front of the light. MegaPOV will fire photons at the whole object,
> since planes are infinite, you will get a lot of photons fired at
> portions of the object that won't effect the results, and a lot fired
> into space. Try a 0-thickness box instead, or triangles or a polygon.

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