Kirk Andrews nous apporta ses lumieres en ce 12-12-2006 12:23:
> Thank you, that was very helpful--

>>   Some basic vector math knowledge could be of great help when designing
>> thing with POV-Ray... :P

> In my defence, I am relatively new and to me, a "vector" is a *direction*
> (which could be defined in various ways).  Yet what is returned is
> obviously three float values combined in what POV calls a "vector".

> Therefore, the normal vector could define a point 1 unit (or more?) away
> from the intersected point in the perpendicular direction, or could be that
> point minus the intersected point.  So I suppose my real question is: How
> exactly does POV define its vectors?

> In any case, you've certainly answered my current problem and I appreciate
> your patience with my ignorance.

> Kirk

In fact, a vertor is a direction PLUS a distance. It can be defined as 3 angles 
and a distance, OR as the end point's coordinates relative to it's starting point.
In 2D, it's an angle plus a lenght or the 2D coordinates of the tip relative to 
the start.
A normalised vector is a vector witch is 1 unit in lenght. Normaly, the normal 
vector returned by the trace function is such a vector.

-- 
Alain
-------------------------------------------------
Make yourself a better person and know who you are before you try and know 
someone else and expect them to know you.

Post a reply to this message