Here's another answer from another co-worker brainiac:
There are a number of ways this could be done, depending on how you want the tube’s joint to look:
1) Draw the path out using a polyline (or 3d polyline) and extrude the circle around that. This has a chance of slightly offsetting the pipe, however, depending on the complexity of the path and the location of the polyline in relation to the circle. If the polyline is at the top, the center, or a cardinal edge of the circle (right or left tangent), it may also have an effect on whether the corner is curved or sharp; I think this also depends on the version of CAD.
2) A slightly more complex way – Extend the tubes past each other, change the UCS to the plane of the bisector of the arc (you could geometrically construct this), and slice both spheres. The critical thing is that the planes of the sphere match. This is somewhat more problematic, as it is more complex (especially if you union them) and you might get the dreaded coexistent face problems or even, Heaven forbid, uneditable solids if it goes too far. This is guaranteed to get a curving face.
Of course, these are both Boolean solid methods of modeling. If you wanted to make the tubes hollow, you could offset the circle you extrude to the inside of the initial circle, offset the polyline path to match (if applicable), and extrude around the offset things. Since they are using ‘revsurf’ instead of ‘revolve’, this is a somewhat different method (make a mesh?)
If that makes sense to you....GO FOR IT (actually, I do get the gist of it) Are you just learning CAD, Mini, or have you been working in it?
