lines of the linked CAD file move when I zoom in and out

[raysanziaei]

I linked an AutoCAD file to my Revit model. For some reason when I zoom in and out the lines of the linked file move . I flattened the CAD file but still does that. What can be the reason? It is a CAD file from our Civil engineer. Also, when I want to draw a detail line and select the pick lines and click on one of the linked file lines, it draws a line not on that line!!  What can be the reason? how do I fix this? Any help is really appreiciated

[ToanDN]

The CAD file may have linework more than 10 miles from the internal origin.  Uncrop the view, zoom extent and see if it is the case.  If it is, you need to open the CAD file and delete lines too far from the project area, or WBLOCK only the relevant part of the drawing to a new DWG and link it in Revit instead.

[syman2000]

Sadly civil drawing always produce wiggly lines when you link into Revit. Civil is based on UTM coordinate which Revit has trouble translating when it is 20km (10mile) away from the original point. To overcome this, you may have to move the civil file closer to 0,0 in CAD so it will pick up as non wiggly lines.

[benoit.lachapelleAWRUE]

By moving the civil drawings closer to 0,0,0, don't you lose the shared coordinates embeded in into the drawings? 

[SteveKStafford]

Not if you use Acquire Coordinates after positioning the file near the Revit internal origin FIRST. The recommendation is to link the DWG using Auto - Center to Center so it starts out closer to the origin but it should be moved so the relevant part of the site file is located near the origin.

[pdent1]

We encounter this issue all the time. My workflow is to draw a line from 0,0 to a known location in the civil CAD. Then move all the linework from the endpoint of that line to the 0,0 point. Then link and align/rotate the CAD, with the long line still visible. Then edit the CAD file to remove the line. If the civil CAD contains multiple files you will have to do this process with all of them.

[curtisridenour]

i 100% agree with you. I do this in the Site model so the line bouncing does not happen within the ARCH/MEP models.

[SteveKStafford]

FWIW, it isn't necessary do this, and alter someone else's file, IF Revit does not generate a warning about the file's extents. Revit doesn't care about the DWG elements being far from the DWG's origin. It does care about the distance between elements within the file (X/Y/Z). If that distance exceeds Revit's threshold of 20 miles then that's going to generate graphic issues. It's not unreasonable to ask the source of the DWG to clean up their file so that it doesn't generate a warning in Revit.

[pdent1]

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It's not unreasonable to ask the source of the DWG to clean up their file so that it doesn't generate a warning in Revit.

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Maybe not, but they refuse anyway and claim there is a legal reason they cannot. After arguing this point for a while I just got familiar with the workflow.

[SteveKStafford]

That's amusing, a legal reason they can't remove elements that are more than 10 miles from the site? Best of luck with them...

[sepideh.m]

Thanks for the tips, I tried and it solved some of my issues, however, I am still struggling with the coordination in Revit. 

- I have georeferenced files in DWG, which are far from 0,0,0 point. (Survey and design file)

- I copied them to move all the contents of both files close to the 0,0,0.

- I ensured that all contents were close enough and within a rectangular at the same location in both files, in order to make it easy to set and check the files.

- I linked both files to Revit, using Auto Center to Center as you suggested. The files' location relative to each other is correct. The SP and PBP are 0,0,0.

- I used Acquire Coordinates and selected the Survey file. The files' location relative to each other is still correct. The SP is 0,0,0. The PBP have been moved with files to somewhere further.

- I exported as a dwg file using "shared coordinates" to check whether the location is georeferenced and correct. But it's not. The X is somehow really close to the correct figure, although not exactly. But the Y figure is far from what should be.

I'd appreciate any suggestion on what I'm doing wrong.