# point from bary coords

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On 20/10/2005 at 07:13, xxxxxxxx wrote:

User Information:
Cinema 4D Version:   9.5
Platform:   Windows  ; Mac  ;
Language(s) :     C++  ;

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Hi,

does anybody know how to compute a point in a triangle from its barycentric coords (that I got from the Ray collider engine)?

Or any links to that topic?

Thanks

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On 20/10/2005 at 07:55, xxxxxxxx wrote:

ok, got it. It´s just a weighted sum of the coords. :)

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On 22/10/2005 at 16:02, xxxxxxxx wrote:

Hello Katachi,

can you explain how to do the weighted sum?

Cheers
Renato T.

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On 22/10/2005 at 16:29, xxxxxxxx wrote:

Take all of the x-coordinate values, sum together, and divide by the number of x values (three in the case of a triangle). Do the same for the y and z coordinate values.

T.x = (A.x + B.x + C.x) * 0.3333333;
T.y = (A.y + B.y + C.y) * 0.3333333;
T.z = (A.z + B.z + C.z) * 0.3333333;

By weighted, I think he means 'average'. If you were going to weight the sum, you might multiply each value by some weighting value. If this is the case, then it becomes:

T.x = ((A.x*wA)+(B.x*wB)+(C.x*wC))*0.3333333;
etc.
where wA/wB/wC are weights applied to each point's coordinate component.

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On 22/10/2005 at 16:33, xxxxxxxx wrote:

ok thanks
I did the same things to get random coordinate in the triangle :)

cheers
Renato T.