function SegmentsPerpendicular(x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4: Double): Boolean;
var
Dx1, Dx2: Double;
Dy1, Dy2: Double;
Dz1, Dz2: Double;
begin
{
The dot product of the vector forms of the segments will be
0 if the segments are perpendicular
}
Dx1 := x1 - x2;
Dx2 := x3 - x4;
Dy1 := y1 - y2;
Dy2 := y3 - y4;
Dz1 := z1 - z2;
Dz2 := z3 - z4;
Result := (((Dx1 * Dx2) + (Dy1 * Dy2) + (Dz1 * Dz2)) = 0)
end;
(* End Of *)
// vérifie si 2 droites tridimensionnelles sont perpendiculaires