CAD links disappearing and showing up wrong when re-linked

[m_whitehead]

I'm at a loss and not sure if this is more a Revit problem or CAD problem. I'm working on a Revit project with multiple CAD links for different floors, and the links keep randomly disappearing and then acting strangely when I try to re-add it. For example, here's what happened today:

I was working in my Revit model on level 1 and everything looked normal. At some point, I'm not sure when (I'm thinking probably one of the times I saved), the level 1 CAD file link disappeared. I opened 'Manage Links' and it wasn't showing there at all. The CAD file location never moved or changed in any way during that time so that couldn't be the reason. I think to myself that's fine, I'll just add it in again. I add it back in and everything looks okay for the overall level 1 floor plan, but then I checked the level 1 furniture plan and floor finish plan and on those views only it's showing all the things I hid or even deleted from the CAD file. I opened the CAD file to check and, sure enough, it looked normal and wasn't showing any of that extra stuff. Since those aren't showing up in the linked CAD file, I have no idea how to get rid of them. What is going on here?? I've included some screenshots to help show what I'm talking about. It's the same DWG import, showing different things in different views. 

Some more details that might be relevant:

- Versions: Revit 2022 and AutoCad 2020

- I'm the only on working on this model, it isn't a workshared file

- Different CAD links have disappeared before, but this is the first time it's showing unwanted items in certain views

- The furniture plans and finish plans were created by copying the overall floor plan, but they were NOT copied as dependents

- I've been linking all the CAD files for the different levels to all views and just hiding them in the views where they don't apply

- Not only is it showing things that were hidden/turned off in the linked CAD file in certain views, it's even showing things from an OLDER CAD file for the same level. For example, it's showing two different furniture layouts from two different CAD links, even though the older CAD link was from a completely different file that's now been deleted, I had deleted the link from Revit, and it's not showing up in the 'Manage Links' window anymore either.

Hopefully I'm making sense at least a little bit because this whole situation is baffling to me. 

[mphungDCHNW]

Hi,

are you linking a floor plan of the furniture in the second picture is that the one of the links your talking about ?

[m_whitehead]

Both pictures have the same CAD link, Level 1.dwg, so I'm extremely confused why they don't appear the same. The second picture, the furniture plan, is showing all these old furniture blocks from CAD that were hidden/deleted from the dwg, and some are even from a different Level 1 link I previously used that has since been deleted (both from the Revit links list and the file itself).

The third picture shows the dwg link opened in CAD so that's what it should look like (the first picture is showing it correctly).

[mphungDCHNW]

I think rather then importing a link of a cad floor plan just import as "CAD IMPORT" and that should work.

Links are for actual model based elements. 

[ToanDN]

Certain layers are turned Off in one plan and On in another?  Share the DWG.

[barthbradley]

The CAD just look misaligned to me.  If Coordinates are Shared, I would suspect that the Survey Point got moved or, if there are multiple Sites, the wrong Site Name was picked when reloading the CAD via Shared Coordinates. 

[ToanDN]

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@mphungDCHNW wrote:

I think rather then importing a link of a cad floor plan just import as "CAD IMPORT" and that should work.

Links are for actual model based elements. 

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I don't usually counter others' suggestions as they genuinely try to help, but I am making an exception this time. 

@m_whitehead Importing CAD has been know for causing issues down the line in the Revit model, plus you will be adding a bunch of garbage to line styles, fill pattern, text styles and whatnots.  Keep the DWG as link and fix them instead.

[m_whitehead]

Thanks for your suggestions everyone, I seemed to have found somewhat of a solution. I realized when linking the CAD file I forgot to select 'Visible' under the Layers/Levels option so now that I've done that all that extra stuff isn't showing up anymore.

I'm still confused why it was showing up differently on different Revit views before I selected Visible, or why there were things showing that aren't in the linked CAD file at all (even the hidden layers), or why my links keep disappearing from the project in the first place so I have to keep re-adding them, but oh well. This works.

[barthbradley]

Duplicate instances of a linked CAD file in the 'Imported' category for Visibility Graphics in Revit...

[barthbradley]

I thought I'd jump back in to explain why I posted that link yesterday.

The odd behavior that you are wondering about, might be related to copying a CAD Link a the Project View via "Create Similar " on the right-click contextual menu. Are you doing that?  If so, be aware that you do this, it creates a copy of the Link in the Project that is disassociated from the Parent Link.   Those "copies" will not be affected when you reload the Parent Link. 

Test this:

1. Start a New Project and Link a DWG into Plan View.

2. Inspect the Imported Categories tab under the View's Visibility/Graphics Overrides and note that only one DWG is shown.  

3. Right-click on the Link in View and press "Create Similar" in the drop-down menu.  Follow prompts to place instance of copy.  

4.  Inspect the Imported Categories tab under the VGOs again and note that two DWGs are now shown - one being the copy.  

5, Open Manage Links and note that only one DWG is listed under CAD Formats - not two. Select DWG Link row, press "Reload From..." and choose a path to a completely different DWG.  

6.  Note that the DWG Link COPY is unaffected in the View. It is still the same. Only the Parent DWG Link changes to reflect the new DWG that was just reloaded.  

So, I think Create Similar is your culprit.  That's my guess, FWIW.  

Hope this helps.