Hi Ed - From my experience - unless it has changed - you are stuck with either round ducts or square ducts on a system wide basis. You cannot mix and match.
I did some experimenting. You can change the setting while you are in the middle of an edit session by going to Customize > Conduit Manager Options. While you can toggle back and forth between square / circle ducts many times within an edit session, each conduit system can only have a single shape type that gets baked into the conduit package when you create its configuration. One of the things I'm noticing, and this may be a bug, is that all of my ducts on my diagram are coming out to be circles even if the conduit configuration is rectangular and my CM settings in my session are rectangular.
James Wright checked into the options for this. Seems the way to get square ducts in the UFM Duct class would be to create Ductbank Favorites with the UFM Diagram Manager and define the duct geometries as squares rather than circles.
Thanks much for the feedback!
Toward this end, it is nice to know about a few editing tools:
If you do not have a duct already (in other words, you are not trying to convert an existing duct):
-Rectangle, found in the Advanced Edit tools category. This tool would allow you to create a perfect square for your duct.
Tip: When using this tool, right-click and check the option for Horizontal; this will keep your duct parallel with 0 degrees
Tip: To make a square, simply input the same distance for length and width
-Circle, found in the Advanced Edit tools category. Same thing as above, but allows you to create a perfect circle.
-Right-Angle Tool, found in the sketch palette. Sketch while using this tool to create right angles. You can also right-click to input lengths for your line segments.
If you already have a circle duct, and you would like to reshape it into a square:
-Don't forget about the SHAPE field in the ArcFM Attribute Editor. Select the circle duct, in the Selection Tab click the pencil in the shape field, and then draw the new square shape using the right-angle tool. Then, update your new shape. It will keep the existing attributes. Finally, as James Wright stated, save this work as a UFM favorite if you'd like to leverage your duct bank configuration of squares and circles on other walls.