Here at the IMAGINIT blog, we love using multi-body solids. Mark wrote a great post on the theory and practice of multi body solids a while back. And while skeletal modeling is one of the most common ways to use multi-body solids, it seems like I am always finding a new use for them.
Take this part for example. It seems simple enough, but the side walls both angle in towards the center and run from the quadrant points of the lower arc to the quadrant points of the upper circle. Hmmm…interesting.
I am sure that there are many ways to accomplish this, but I used multi-body solids to get the job done. Here is how I did it.
I first created the top cylinder and the bottom half cylinder. The dimensions for the side walls were based off of this, so it made sense to me to start there.
As I mentioned before, the side walls slope in two directions. I will start with the slope in towards the center. What I am doing at this point is drawing the front view of that side wall. I will not join this solid at this point. Instead, I will use the New Solid option on the extrude dialog box to create a new solid. This creates a new solid body in this part file that can be edited separately from the rest of the part. That becomes important in a moment.
Now I will mirror that to the other side to create the other side wall.
Of course, this is not the final shape. To fully describe the shape of my side walls, I will create side view of the side wall on the plane running down the center of the part.
Now I can extrude this sketch. Using the Solids button on the Extrude dialog, I can control which solid(s) are going to be affected by this extrusion. I will choose the existing side wall, and I will choose the Intersect option. This will keep whatever is common to the two solids.
Now I can use the Combine tool to join the sidewalls to the rest of the part. A few more extrusions, holes and fillets later and boo-yah! A shiny new part created using multi-body solids. Cfunk out.