Revit DWG snap bug and wonky lines

[Anonymous]

When snapping to edges from a linked cad file, the actual snap point doesnt align with the lines from the dwg (as seen in the image above)

In the same project, dashed lines appear wonky. I have tried changing the view scale, and disabling hardware acceleration, but the issues persist.

I have never had either of these issues before, so i have clearly done something, or something has broken in this file. Any ideas?

Thanks

[Sahay_R]

Try to link the CAD file into a clean project. Do the issues persist? If not, the next step would be to link the clean Revit project into the desired project.

[Anonymous]

Must be the CAD file then, since the snap bug still happens in other projects & versions of revit.

The wonky lines however, don't happen in other projects

[Viveka_CD]

Hi @Anonymous

Can you share the file to test further?

Please try the following steps for me and let me know if this helps resolve your issue:

1. Open the DWG file in AutoCAD 
2. Enter AUDIT.
3. At the "Specify whether you want to correct problems found by the audit" prompt, enter Y.
4. When the audit is complete, save the DWG file.
5. Link the repaired DWG file to the Revit project.

Regards,

[Anonymous]

Hi Viveka,

I have tried the audit command in CAD, but it didnt correct the issue.

I have linked a quick test file with the linked CAD file and a wall with a window in. As you zoom in and out on the window you can see the cad file dance about.

files:

https://www.dropbox.com/sh/9jbmqrodcv337al/AAB2DEclS-mKVRfD-lJKJNm8a?dl=0

[andybrack · Accepted solution]

Most often this is a result of the extents of the CAD file being very large, and I mean in the thousands of feet.  I've noticed your same problem mostly with civil engineering site plans, but have also seen this with architectural floor plans too.  The imprecision stems from the way Revit is trying to perform the math with such large numbers that the precision goes down causing the weird line and snapping issue. My suspicion is that the linework in the cad file is far away from the 0,0 point in the cad file.  Another possibility is there is an object in the CAD file that is (to quote Star Wars) 'in a galaxy far far away' from the plan elements such as an errant point, line, or a leftover block.

I've found that the best solution is to clean up the .dwg file in AutoCAD by zooming out a lot, then use a selection window to try and find the 'far away' objects.  Assuming you find something, delete it.  Then use the Zoom Extents command to double check that the limits of the drawing more closely resemble what you are expecting (site or building).

If you can't find any errant objects, use the Export to AutoCAD command (in AutoCAD) as this may help correct the extents. This is all predicated on the assumption that you have Linked the CAD file in Revit as opposed to Inserting.

I hope this helps,

Andy Brack

[Anonymous]

Thanks!

TIL about moving cad drawings to 0,0,0 before linking them into revit!

[Viveka_CD · Accepted solution]

Hi @Anonymous

Glad to hear that the solution by @andybrack helped resolve your issue.

You can use "base" command to redefine basepoint.

Also, see this article HERE regarding preparing your dwg file before linking into Revit and how to have a clean/optimized geometry!

Regards,