Interior dimensioning would work for this, but the method I use is: select all walls in one direction, start the tool, draw a line through the walls, complete the line, place dimension. Repeat for the other direction.
However I am also quite quick with just using CTRL to add extra dimension to an existing line by clicking the walls.
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nlArchiCAD 9-26NED FULL
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