CAD links keep disappearing

[PDSF]

We have a new project which we are hosting in BIM360. I just linked the civil files. There are three civil files and there will undoubtedly be more, so our practice is to create a "master" file which the three others are linked into, to keep them aligned with one another. Then I uploaded to BIM360 using the "upload linked files" option. It appears to work temporarily, but the links keep disappearing, leaving only the master file (which has no information of its own). The worst part is that each time they disappear, so do their layer settings in the view templates. We obviously can't continue this way. Anyone have any ideas what's going on? TIA.

[PDSF]

I should add that I prepared the CAD files for upload by:

- removing all xrefs (except the master file)

- setting the master file xrefs to be relative

- purging all regapps

- purging all unused elements

- audit

[SteveKStafford]

Sounds like you're not using Autodesk Desktop Connector (ADC)? For links other than RVT Autodesk supports making them available thru ADC (think Dropbox by Autodesk). Each person that accesses the file needs ADC installed so it can sync these support files across the project team.

The files go missing when a user that can't "see" the path for the linked files. ADC provides the continuity for the "path" by creating a BIM360 folder you access to store and link the files. ADC syncs that across each user and their own BIM360 folder.

[PDSF]

Thanks for the response Steve. I definitely am using ADC, and in fact updated it recently. I will check with the staff to make sure they all are as well.

[PDSF]

Confirmed, all users have Desktop Connector installed, running and up to date. Any other ideas?

[SteveKStafford]

My guess is the master/Xref linking process. Try linking each DWG into the RVT individually and see if that is sustained, it should. I suspect that the Xrefs are lost in the master because they were defined based on a different local path during the Insert process. You can also try using Xref Attach and browsing to the BIM 360 location to "find" the xrefs.

If your RVT has Acquired Coordinates from one of the DWG files then each of the others can be Linked using By Shared Coordinates and Revit will use the World Coordinate System (WCS) of each file to align to the Survey Coordinate System. That assumes you can Xref any of the DWG file together and they line up in AutoCAD based on the same WCS relationship.

[PDSF]

Thanks again Steve. This is a little beyond my Autocad abilities. It's been a long time since I used it. But we create the master file because the three links are not even at the same scale and need to be rescaled to line up with one another. They also need to be rotated to match our views. The link was inserted manually, not via any kind of Revit alignment.

The whole UCS issue in Autocad is way over my head, I never understood it back in the day. The civil engineer sets their origin somewhere in the middle of the Pacific Ocean and insists they can't change it. But the positioning is stable, that isn't the problem. The master file approach is what has worked for us in the past, on far more complicated projects I might add. Those were in v2018 and I can't help but think this is a 2021 bug.

[SteveKStafford]

You can try setting up the Master DWG so that the Xrefs are located in the BIM 360 folder too. I assuming the path for the xrefs is currently a folder location on your server. If true that's probably what is "wrong".

[PDSF]

No, all four CAD files are in BIM360. As stated above, all paths are relative anyway, and the drawing looks fine in the BIM360 browser window.

[SteveKStafford]

Did you add the xref's while the files were on BIM 360? Does the Xref path show the BIM 360 location?

[PDSF]

As noted above, I added the files to BIM360 using the "upload linked files" option. Prior to this the master file only had relative paths directly to the sub-files, no paths at all. Again, this has worked for us in the past.

That said, for whatever reason, the links seem stable today. I will chalk it up to a BIM360 glitch for now. Thanks for your help and I will post again if the problem recurs.

[SteveKStafford]

Yes I saw that, which I assume is to blame. BIM 360 infrastructure is frequently updated...so what worked in the past is no guarantee. If the Xrefs are added to the master file using the ADC BIM 360 path I suspect you'd find it is more reliable/stable. The relative path might still not work if that path is a local folder on your network but not another member of the BIM 360 team.

Then again as you wrote...it might have just been a glitch in the hosting system...hopefully it doesn't rise again.

[PDSF]

Hi Steve. The problem has recurred, and I actually had an hour long zoom with an Autodesk tech rep today. He is going to try to figure it out. I can repath the xrefs to the BIM360 location and see if that helps.

[PDSF · Accepted solution]

As it turns out, you can't repath the links to the BIM360 location, at least not without detaching and reinserting them which I don't want to do. All I could do is "remove" the path. We'll see if that helps at all.

[SteveKStafford]

Well hopefully Autodesk support can get it sorted out. I suspect you'll be faced with recreating the master by attaching the Xrefs using the BIM 360 folder path and (ADC).

[SteveKStafford]

:deleted:...duplicate post, glitch during posting

[PDSF]

Removing the path seems to have stabilized and hopefully fixed the issue. Thanks for your help Steve.