Take a look at the attached screenshot.

See that oddly-positioned rod? One end of it is supposed to be in one of the spheres shown, and the other end in the other sphere. It's supposed to connect these two snaps.

What I had in mind was that I will set the rod component to be Flexible, and then I could move the other components in the assembly as I wish, and have the rod automatically conform (have it change its length, position and angle to connect the two spheres.)

But I find that when I move components, the rod takes a non-sensical position as shown in the screenshot.

How do I make the rod always connect the two spheres? Note that the rod is a boss which is in a subassembly. The way I made it be from one sphere to the other is create two points for the center of each sphere, create an axis between them, create two planes (perpendicular to the axis, coincident to each point) and then start a boss with a sketch from one plane and have it terminate in the other. I also tried setting mates between each end face of the rod to the sphere-cutting plane, but that didn't help either.

Any idea what to do?

Thanks,

Ram.