Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
Drexel University or The Math Forum.
|
|
|
|
Re: Intersection between two cones
Posted:
Feb 6, 2013 6:21 AM
|
|
"Doctor61" wrote in message <ket0to$214$1@newscl01ah.mathworks.com>...
> 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?
if centre is x1,y1,z1 and radius r set d^2=x1^2+y1^2+z1^2
Cone is intersection of spheres a^2 (d^2+r^2)=x^2+y^2+z^2 and
a^2 r^2 = (a x1-x)^2+(a y1-y)^2+(a z1-z)^2
Eliminate a to get equation of cone:
x^2+y^2+z^2 = (r^2+d^2) (x1 x+y1 y+z1 z)^2/d^4
(check this)
Set x^2+y^2+z^2=1 and solve for points on two cones and this sphere.
E.g. Solve linear equations (1= (r^2+d^2) (x1 x+y1 y+z1 z)^2/d^4 etc)
for x and y then substitute into x^2+y^2+z^2=1 to get quadratic for z.
Regards
|
|
|
|
