Re-Scaling a drawing

[Anonymous]

Hi, very new to AutoCAD, but learning the basics quickly, and enjoying it.  This one is stumping me though.

I have opened an architectural drawing of my building.  Everything looks as it should, but when I go to measure in model space using the measure tool, the measurements are showing as very large.  EG, a wall that should be 3'2" is measuring as 82'11".  I suspect that there is something really simple that I am missing/don't understand.   There's no reason I can think of that it would have been drawn at such a large scale in the first place.

I am not talking about annotations, I have those layers off and will attend to their scale later.   

This is an ongoing issue for me with other drawings - so any help would be so greatly appreciated!

[JPomeroy]

Did you make the drawing?  The view you gave (I assume you can't post the .dwg file so we can verify?) looks like you are indeed correct, and that dimension is a pretty unlikely 82' and change...  That's a darn big door!  All drawings in model space should be drawn in 1:1 scale; 1:1 is set as the scale, but it either wasn't drawn that way, or it was changed at some point.

There are simple scaling tools, that can correct this for you, but before you rescale the drawing, you should be sure.

To rescale the drawing, if you know even one dimension's real value (a door width, a wall length, whatever) you can use:

SCALE command

select all the parts of your building/drawing/whatever

R for "Reference"

it will ask you to select two points.  Choose the endpoints of a known value, if you know wall A is 4' wide, select the ends of that wall.

AutoCAD will then ask for the new value.  Tell it 4' (include units) and hit spacebar/enter.  Voila!

https://knowledge.autodesk.com/support/autocad/learn-explore/caas/sfdcarticles/sfdcarticles/How-to-p...

[pendean]

What program was the original DWG created in?
What unit of measurement was the original building drawn with?

Post your DWG file if you can.

[h_s_walker]

Sounds like you've got imperial and metric messed up together

3'2" in inches is 38 inches

38*25.4 (mm in an inch) = approximately 965

965 /12 = approximately 80'

[Anonymous]

Thanks for your reply.

I did not draw this, it is a dwg from construction/reno of the building a few years ago.

I am happy to try the scaling solution, but can I do that to the whole drawing?  Do I just select everything manually?

The DWG was drawn in AutoCAD, I am assuming.  I should note that when I first opened the file, I changed units from MM to Feet/Inches

[JPomeroy]

Nice catch, @h_s_walker!

[JPomeroy · Accepted solution]

So, you confirmed what @h_s_walker found.  When you use the UNITS command to change the units, it doesn't automatically adjust the drawing.  It just assumes the numeric value given to any line is now in the new unit you selected.  So, what was a 1m length is now 1 inch, or whatever.

To use the reference method, to select everything, just zoom out so you can see the whole drawing, and click (don't hold) the left mouse button until you see either a blue (window selection) or green (crossing selection) box start forming.  Cover your whole drawing with the box to select it.

Window vs crossing selection is a useful difference, but won't matter for this purpose.

https://knowledge.autodesk.com/support/autocad-lt/learn-explore/caas/CloudHelp/cloudhelp/2017/ENU/Au...

[JPomeroy]

https://www.youtube.com/watch?v=i4ppTaJnJUY

Try that, so you can see someone using reference scaling in action.

[Anonymous]

Thank you all, the scale tool with reference point worked a treat.