Le 04.11.2007 17:16, alphaQuad nous fit lire :

> apparently I am in similiar company as no else can either.
> 

Stop whining... it won't help to get any result.

> the task:
> Area = abs(   (xB*yA - xA*yB)  + (xC*yB -x B*yC)+( xA*yC - xC*yA ) ) /2

This formula looks bogus.

We already know that

Area = || AB x AC ||
           -------------
                   2

Let's make a numerical application with A(0,-1) B(1,0) and C(0,1)

 abs ( (-1 - 0) + (0 - 1) + ( 0 +1 ) ) /2 ---> abs ( -1 ) /2 --> 1/2
(wrong)

AB: <1,1,0>
AC: <0,2,0>

AB x AC: <0,0,-2>

Area = length(AB x AC)/2 = 1. (good!)

> 
> make shortest 3D version

The crossproduct is fine, what do you need ?

-- 
The superior man understands what is right;
the inferior man understands what will sell.
-- Confucius

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