I’m making something that essentially consists of a cylindrical shell with some features on the inside. I’ve pushed/pulled the majority of the center out from the bottom and am left with this.
But it still considers the entire top to be the face. How do I tell sketchup I want that feature to become its own face, with that arc as a border? I’ll then push/pull the feature back down to the desired height.
How about uploading the SKP file so we can have a look? Generally a problem like that would be caused by the arch not being fully on face or not actually intersecting with the corners at the ends.
Your file didn’t have that arc drawn in so I went ahead and did what I think you want to do. Instead of drawing an arc between the corners, I just used Offset to offset the outer edge to the inner edge. This will result in skinning over the entire thing but that inner face is removable. To show that the division happened I pushed the faces on the inside down a little.
Since I couldn’t see your arc, I don’t know why it didn’t separate the surface into two. Most likely one or both of the reasons I outlined before. Offset is easier and more accurate in this case, though.
