"Doctor61" wrote in message <firstname.lastname@example.org>... > I have two 3d circles (centre coordiantes and radii) with their normals passing through origin. If you consider the origin to be the vertex of a right cone having the circle as the base, how can I determine if there is an intersection between these cones?
I believe the intersection is two lines passing through origin. You "just" need to scale appropriately the base circles so that they intersect in 2 points. That will give you two points of the intersection lines.
It should be doable to do the first task using FZERO and writing few equations of circles. For example the two plane that carries the circles must be intersected as a line.
1) Compute the 2 x two points of the 2 circles falling on this line.
2) Then compute the algebra distances those two pairs of points projected on the line. (chose some arbitrary origin on this line).
3) Varying the distance of on base circle and find the place where the algebra distances in (2) match using fzero.