On Tue, 26 Mar 2002 10:40:41 -0600, "Shay" <sah### [at] simcopartscom> wrote:

>Povray finds the angle between two vectors like this like this: acos(min(1,
>vdot(vnormalize(V1), vnormalize(V2)))) What is the purpose of the min()?

acos is defined over [-1; 1] because no angle has a cosine greater
than 1. However, with computers, it is perfectly normal to have as a
result something like 1.0000000098345352 when you need 1, which, in
this case, will trigger a floating point exception. Hence the min.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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