Autocad Map 3D 2010/Revit Arch. 2012 Problem

[Ryan Cockerill]

Hi,

My name's Ryan, I've been using Revit Arch and Struc for about 2 years. Recently we took a job where the surveyors gave us a CAD file designed with AutoCAD Map 3d 2010. The CAD file seem's to be fine in everyway from what i can tell, however when we bring it into Revit as an underlay its scaled approximately 110 [and change] times down from what's needed. After scaling up the file so much it becomes virtually unusable. I've been in contact with the company that provided the file and have been told they model everything at a 1:1 scale and they do everything 'unitless'. I'm trying to bridge the gap between CAD and Revit with little luck. Any suggestions as to how the surveying company can modify their file to be bigger as an exported CAD file, reducing the amount of scaling we need in Revit?

Addendum: If i take the CAD file and scale their drawing up (changing dimensions etc from their actual value) the file stabalizes in Revit.

Thanks ~
Ryan.

[david_peterson]

How from from the 0,0,0 origin is the cad file. If it's a very large number I'd move it closer to the 0,0 point and make sure there's no base point set.
If it was done as a decimal drawing is 1"=10' you may need to scale it up by 12. Again I'd do this in cad. Purge the dwg file, audit it, clean it up as much as you can, and then try to link it. As much as they like to think that Acad and Revit play well, they don't like to play in the same sandbox.

[Ryan Cockerill]

Units were not specified in the CAD file, but thanks for the help.

[david_peterson]

Set to arch units, take a quick distance measurement.
If it seems like it's 1/12 what the correct distance should be, scale it up by 12. Most site drawings are done in decimal feet. Changing units to arch and scaling should help the problem. Again, make use the 0,0,0 of the WCS in the Acad file is somewhere close to the actual site. I'm not sure what the limit is as to where it goes bad, but if you're drawing linework isn't close to 0,0,0 you're going to run into all kinds of issues.