Extrusion Tool Woes

I’m still having problems with the simplest operations of the extrusion tool, and it is definitely making me feel like a dummy. It’s simple to extrude a shape across a single volume, but when it concerns connected volumes, I’m striking out. To troubleshoot, I constructed the simple rectangle of individual volumes as shown in the attachment. I want to extrude a rounded edge around the outside of the model. But whenever I exercise the extrusion tool on an arc drawn on the end of the model (after carefully selecting all the line segments comprising the path), I get an “invalid path” message.

Also, typically I design using components, and later might later decide to extrude a shape to add a detail to a finished model. Using the attached model as an example, it would consist of two components, side rails and end rails. But once you have components, you have no ability to simply select a path across all of them, and I cannot get extrusion to work. I’m sure I am, once again, missing the obvious.Extrusion Tool Woes.skp (97.3 KB)

Just to clarify… when you say “extrusion tools” are you talking about Push/Pull or FollowMe?

It must be FollowMe that you are referring to. It works on your shape, selecting all edges on the top perimeter. You could remove the excess and make components afterwards.

Yes, it worked for me, of course, after I posted a “it doesn’t work for me” topic. Thanks.