In article <web.3dd645beb3508d7038149fba0@news.povray.org>,
 "Tor Olav Kristensen" <tor### [at] hotmailcom> wrote:

> As long as his transformation matrix does not scale
> or shear the object in any way, he can just use this
> matrix for the normals as well.

Equal scaling is possible, only unequal stretching needs the transpose. 
But detecting this case takes more processing power than using the 
transpose of an existing inverse matrix, implementing it that way is a 
waste of time. It is easy to make a function that transforms by the 
transpose instead of the matrix without actually going through the 
trouble of transposing the matrix, it is no more computationally 
expensive than an ordinary direction vector transformation.

-- 
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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