Scale> Reference is the solution.
1 Open your dwg and save as- so you do not mess up the original
2 go in MODEL space Delete all the stuff you do not need from the drawing
3 Look for a known dimension on the drawing. (A wall, a door, an opening, anything. Preferably along the Ox or Oy axis, ortogonal direction.) Let's call this AB line. Where A and B are the two ends of the known dimension.
4 If your AB line is along the Ox or Oy axis activate ORTHO mode by pressing F8. this will allow you to draw only along ox and oy axis
5 Now draw a line to the lenght that is called out in a drawing along AB line. This will be line AC and it will be to scale (Example: your drawings call the AB dimension to be 24". draw the AC line to 24" length). Activate the snaps too by hitting F3
6 type SCALE
7 select all your objects that you want scaled (should be all because you deleted all the things you do not need)
8 select as base point the point A
9 now hit R for reference
10 Reference lenght - click on point A and then on point B on your known dimension
11 For new length now click on point C
That's it
double check with
'_dist
command
