Issue with Scale Change When Converting Units from Decimal to Architectural in AutoCAD

[akshay_bapat]

I have a Civil 3D survey file in DWG format with units and annotations in decimal. When I open it in AutoCAD and change the units to architectural (both the drawing units and annotation units), the scale changes. How can I fix this issue?

  

[paullimapa]

Actually the scale of the dwg is not changing. 

100 units is still 100 in architectural.

It's a matter of conversion to get it to read back in inch units:

8 feet x 12 inches = 96

then add  the remaining 4 inches = 100 units

[Kent1Cooper]

To elaborate a little more:  Civil Engineers and Surveyors usually draw with a drawing unit representing a foot.  Architectural units of feet/inches/fractions require that a drawing unit represents an inch.  So as @paullimapa says, 100 drawing units are still 100 drawing units, it's just that the drawing unit represents a different thing in each case.  If you get a drawing in which a foot is one drawing unit long, and you need a foot to be twelve drawing units long instead, SCALE the whole drawing up to 12 times as big.

[akshay_bapat]

Thanks for the explanation. I understand the need to scale the drawing to match inches. However, when I get updated survey information, I'll need to scale the survey DWG again to match my scaled drawing.

Is there a way to configure AutoCAD so that one drawing unit is read as one foot instead of the default one inch? I'd like to import the survey file, work with feet and inches, and annotate without needing to scale each time. Any suggestions? 

[Kent1Cooper]

Look into the INSUNITS System Variable.

EDIT:  To elaborate, open the drawing in which a drawing unit represents a foot, and set INSUNITS in that drawing to 2 so that it will be treated as being drawn in feet, on Insertion in another drawing.  Just for reference when trying it out to demonstrate the effect, draw a 1-unit-long Line in it somewhere, being [in that drawing] one foot long.  [And Save.]  In your target feet/inches/fractions drawing, ensure that INSUNITS is set to 1 (inches).  When you INSERT the Civil drawing into the Architectural one, that one-unit-long Line will be one foot [no longer 1 drawing unit but 12 drawing units] long, with the scaling accomplished for you by the relative INSUNITS settings in the two drawings.

[rgrainer]

Why not xref the Survey drawing?
Scale and adjust as needed, dimensions read correctly.