Add walls to 2D floor plan I have the blueprint of a room in my flat as a planar 2D vertex, example:



I want to add walls to it that are going into the Z direction. I have tried several modifiers and searched with Google, but i have not come up with a fast and easy way to do it. Currently my method is to create a new, second vertex and measure all edge lengths, then recreate the shape and extrude it into the Z direction. There surely must be a better way, maybe with a modifier -- but  how?
Inset the face you have with I, invert the selection (since the area which was inset will remain selected) with Ctrl+I and then extrude.



Note that depending on the case you might need to change topology in the end to convert Ngons to something more appropriate. Though if no subdividing with modifiers like Subsurf is used then it won't be that necessary.