I am trying to write a code that will measure the intersection point of a line and a circle in 3D Space. I have the initial point (x,y,z) that the line begins starts on, and I know the gradient for that line (deltaX,deltaY,deltaZ). I also have a center point for a circle (x,y,z), it's radius, and the plane it lies on (xy plane, xz plane etc...). What I want is to find out is if there is an intersection between the line and the circle, and then if so, what that intersection point is. I'm just having trouble getting the initial set up for the equations so that I can go ahead and start solving for my unknowns. Can anyone offer me some help?