Shane Benson provides another installment of his tutorial series looking at modeling objects with Subdivision surfaces in Cinema 4D, and here he shows methods for extruding a different shape or form from another. As an example, if you have a 3D cube, and need to extrude a pipe out of a face of that cube, or starting with a cylinder and extruding another shape out of the side of the cylinder.
that would mean that you would need to have a square cube shaped object and then model a round cylindrical hole extruded from the cube
It may sound like a simple process, but if you require some sort of edge treatment where the different shapes intersect, such as a beveled edge, then the solution is a little less clear.
Shane demonstrates some simple techniques for creating “transitional” topology in the face of one shape that will facilitate the next extrusion to the second shape. Shane does this by creating a selection of edges by way of a Zero Extrusion, which will offer a simple method for providing symmetrical geometry for the hole in the side of the cube.
If you need to catch up to the rest of the series on Sub-D Modeling in Cinema 4D, check out the previous posts: