"Warp" <war### [at] tagpovrayorg> schreef in bericht 
news:4581a57f@news.povray.org...
>
>  Despite the similarity in the names of the terms, a normal vector and a
> normalized vector talk about two different things:
>
>  - A normal vector is a vector perpendicular to a surface (or line in 2D)
> at a certain point.
>  - A normalized vector is a vector of length 1.
>
>  Thus a normalized normal vector is a normal vector of length 1.
>
>  The dot product returns values between 0 and 1 only if the two vectors
> are normalized.
>  (More specifically, the dot product is the product of the lengths of
> the two vectors and the cosine of the angle between them. Naturally if
> both lengths are 1, the result is just the cosine.)
>

Thanks Warp! This makes it clear for me. Perhaps it would be a suggestion to 
add something like this in the documentation? I think that would be useful.

Thomas

Post a reply to this message