Hi Berube, you can probably just not worry about those edges, in most cases they're not doing any harm and so it's probably not going to be worth the time to try to get rid of them.

Right now there isn't any really easy way to remove those particular kind of edges, you would need to rebuild those particular faces in order to get rid of them.

I'm not sure if you're asking if you need to rebuild the entire model though? That's certainly not necessary, to get rid of the edge you show there you can do it locally by selecting the 2 faces to either side of it, delete those, select the bottom edge, run Extrude and snap the height to the top and then use Edit > Join to glue the new longer extruded surface back into the main object.

In the future I would like to make boolean union remove these kinds of edges and fuse 2 stacked extrusions into a single longer surface. But right now boolean union will only do that type of face merging on 2 planar faces that are coplanar or on 2 faces where the underlying surfaces of the face are coming from the same full surface. In order to remove the edge you show there, a new type of merging needs to be done where it would detect 2 stacked extrusions that could be represented by one extrusion.

- Michael