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Boy, you are a math whiz! But I'm slightly confused in your notation, it's
almost as if you wrote three matrices instead of one. By "determinant of
this matrix", you mean:
A.x * B.y * C.z + .....
Will pov or one of your macros do this calc for me?
John VanSickle wrote:
> Greg M. Johnson wrote:
> >
> > Is there an automatic way to calculate the volume of a 3d mesh?
>
> For each triangle, take the following matrix:
>
> [A.x A.y A.z]
> [B.x B.y B.z]
> [C.x C.y C.z]
>
> Where A, B, and C are the vertices of the triangle. Make sure that
> the order from A to B to C goes in the same direction for each triangle
> (either clockwise or counter-clockwise) when viewed from the outside
> of the mesh.
>
> Take the determinant of this matrix. Divide it by six. If the
> determinant is negative, leave it that way.
>
> Add up all of the determinants for all of the triangles. Divide by
> six. If the sum is negative, make it positive. The result is the
> volume of the mesh.
>
> Note that every edge *MUST* be shared by exactly TWO triangles, or the
> sum will be entirely meaningless.
>
> Hope this helps,
> John
> --
> ICQ: 46085459
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