In article <web.3f187c7a5afdf36ca6ac136d0@news.povray.org>,
 "BorisW37" <Bor### [at] yahoocom> wrote:

> If i have 2 points A <x1,y1,z1> and B <x2,y2,z2>, how do i find coordinates
> of point C <x3,y3,z3> which lies on the line AB, distance D from point A?

vnormalize(B - A)*D + A

Find a vector pointing in the direction of the line (B-A), normalize it 
so its length is 1, scale it by the desired distance, and add it to the 
first point of the line. If you leave out the vnormalize(), D acts as 
the percentage (as a fractional value in the range [0, 1]) of the 
distance from A to B, rather than the absolute distance in units.

Or if you are just looking for the midpoint, (A + B)/2 will work.

-- 
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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