On Tue, 10 Feb 2004 12:44:21 -0500, Christopher James Huff 
<cja### [at] earthlinknet> wrote:

> In article <opr25yj0lyp4ukzs@news.povray.org>,
>  Phil Cook <phi### [at] nospamdeckingdealscouk> wrote:
>
>> You caught me in the middle of replying to Severi; so I'll start again
>> here. Yep I guessed it had something to do with the light plane, but 
>> can't
>> figure out how it works. I'm producing a plane presumely based at 
>> location
>> perpendicular to the point_at so if my location was at 0 and point_at y
>> then then it would be equivalent a plane{0,y} I assume?
>
> No. The point_at vector is a location, the plane vector is a direction
> (the plane normal). Thought the two are the same when the location is <
> 0, 0, 0>, as in your example.

Errr. If light-source{0 rgb 1 parallel point_at y} then surely if I 
connect a line between location and point_at than a plane perpendicular to 
this would be lying at 0 in the XZ plane ie. plane {0,y} and not 
plane{y,y} or even plane{y,-y}; in the same way that light_source{y rgb 1 
parallel point_at <1,1,0>} would produce the equivalent of a plane{0,x} or 
plane{y,x} to be more precise: otherwise the scene I've just produced 
wouldn't work; unless I'm just lucky :)

>> I've just read what I wrote and worked it out: the plane I'm producing 
>> is
>> passing through the box; as the light is taken from the closet point of
>> the plane I'm getting the equivalent of an internal light source. Sheesh
>
> Right.

So I moved the light location to: 
light_source{<-5,20,WindowGap*WindowCount> rgb 1 parallel point_at 
<10,0,WindowGap*WindowCount>} which produces just the right results. Now 
I've figured it out I assume that I don't need to reproduce the lights at 
multiple points as the light plane will cover the entire scene. Though 
just doing a quick render I prefer the extra amount of light; I'll just 
hike the rgb up. Hmm much faster.

--
Phil

-- 
All thoughts and comments are my own unless otherwise stated and I am 
happy to be proven wrong.

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