If you hide all but the floor sheet you can then copy the floor you have drawn onto the walls sheet. Then hide all but the walls sheet and use the Change Properties button to change the fill and line width of the ex-floor. Giving the polygon a line width will make it into a wall around the same shape.

Make sure you also change the layer to WALLS as well as the sheet, and you will be able to cut doors through the walls with the cutting symbols.

Its TRACED, by the way. A newer and better version of the tool.

Before you use it make sure you have the correct sheet, layer and fill style selected as active. It's not a disaster if you didn't do that because you can use Change Properties to put things right again. It just makes things easier and faster.

Thank you, Aramisdante. Are you referring to the very minor role I play in the weekly Live Streams? Those are really Ralf Schemmann's and Remy Monsen's work. I just filter the questions out of the chat stream and feed them to whoever is actually doing the video ;)

I did a blog with an example map of a city on a small mesa, if that is any help. The assets used were all CD3 - no extra annuals or other add ons.

I know your city is at the base of a mountain, but you could use the same technique to make that mountain, or the visible side of that mountain.

(6 symbol connectivity test using the "bright" version of Title A style)