Linked File Display Problems

[ajayholland]

I have a Civil CAD base file where the information is miles (6,612,214 feet) from the WCS origin. Following best practice guidelines, I inserted that file as a block into a ‘host’ file, with the desired origin at ‘0,0’.

When linking this CAD file into Revit, I know that the 2d geometry has been translated, because I do not get the typical error message: “Imported objects located a large distance from the model might not display properly.”

Unfortunately, the display of the linked CAD info is unacceptably inaccurate.

The attached images illustrate the problem. Pre-highlighting or tracing objects shows that the actual position is accurate, but what is displayed is unusable, especially for coordination.

~AJH

[Steve_Stafford]

Try this approach instead:

In the cad file make sure there is no rogue geometry beyond the survey data your really want to show. Use WBLOCK, purge etc...layers on/thawed etc... Identify a benchmark close to the proposed building area and determine what its coordinates are.

When the file is ready then:

Link the civil file in Using Auto: center to center
Adjust the civil file so the area involved is located over the origin in Revit
Use Specify Coordinates at a Point, pick the same benchmark location and enter the correct coordinate values.

This should match up Revit and survey as well as make it possible for Revit to display the lines more accurately. Even AutoCAD suffers from some measure of display inaccuracy if the geometry gets too far from origin, Revit just has less tolerance for it.

Oh and you know I prefer to do the site stuff in a separate file to make it easier to move the building around if necessary :wink:

[ajayholland]

Thanks, Steve for that 'best practice' outline. Unfortunately, it did not correct the problem.

By intuition I w-blocked a section of the drawing and linked that in. When there were no display problems, I realized that this was a file size issue.

Although the linked CAD file was small, only 760kb, it contained a significant amount of data (survey coordinates, point descriptions, etc. 5900 objects). In trying to maintain the integrity of the file, I ignored my usual procedure of cleaning out all unnecessary data.

By saving out only what was needed for display, the file size was reduced to 280kb, object count to 1603, and the graphics now display correctly.

~AJH