A great modeling exercise is to connect like and non-slice parts together. That is why when I teach modeling, one of the first things we do is build a sharpened pencil. Creating the transition from a hexagonal cylinder, to a round one requires some thought and a few tries. It’s a great way to start thinking about topology, and edge strategy. Same holds true with pipe connections.
Creating pipe connections can be easy with some forethought. One must keep in mind that there are varying types of pipe connections, so the challenge can range from the “ridiculously easy”, to the “not so easy as once thought” realm.
Recently, a few videos came through from a c4D user “contrafibbularities“. The tutorials are short, but cover how to think through, and model various pipe connections in Cinema 4D. Starting with a simple T-connection, which can be simple if you think ahead. Other videos look at modeling a 45° pipe connection, while another looks into “welding” two cylinders together. All important in their own processes.