CAD layers resetting when refreshing Linked CADs

[challstrom]

Posted this in MEP, hoping here it will get an answer.

We are working with an Architect that uses AutoCAD. We link these files as background for our work. Inconvenient, but workable. Using Revit 2022.

We occasionally receive an updated background from the Architect. The new file has the same name and same layer names, just revised linework. When we reload the linked CAD file, the CAD layers  found under the "Imported Categories" tab reset. This forces us to go through and turn off the entire list of unwanted layers across multiple disciplines.

They reset for views with and without templates assigned. I've made sure the CAD VISRETAIN variable to is set to 1. This happens when we "Reload From.." or "Reload" in Revit. I've tried with the "Preserve graphic overrides" both on and off.

I can set a view template, but the CAD layers still revert to visible. This happens inside a view template (if one is applied) or in the view itself (if one is not).

Steps to recreate are as follows:

• Create a new Revit project from built-in template.
• Save it to a location.
• Link CAD file Version1 (either local or BIM360. I've tried various CAD files).
• In Revit go to Visibility/Graphics-Imported Categories and turn off some layers.
• Copy CAD file Version1 to new file Version1 (in different location to avoid naming issues).
• Replace old CAD file with new CAD file (if using the "Reload" option).
• In Revit reload (or "reload from...") CAD file.
• CAD layers in Revit revert to visible.

The problem doesn't exist if the linked file is edited, but only if replaced/reloaded.

Anyone have a thought or solution? Can anyone verify that they get the same issues?

[syman2000]

Can you check if the Architect CAD has override linetype, color and Lineweight? This will often override whatever setting inside Revit. Most often I override the element and turn them to black so I wouldn't bother going thru each layers resetting them.

Also Revit has a weird visibility reset issue if object within a block is given overriding layers, color and lineweight. Even if the block is placed in the correct layer, Revit treat the object layers in the block as newly override. It is very annoying. Most often I would cleanup the consultant CAD before bringing into Revit.

[challstrom]

@syman2000  Thanks for the reply!

Upon receiving the CAD from the architect I go through and clean it up. Bind-insert the xrefs, explode all blocks, clean up layers (merge and delete), audit, and purge. I've got a LISP that does most of it automatically.

But for some reason, I cannot replicate the problem any more. 😲 😵 😠 It was a pain last Friday (2/25) but no longer.

I'm not sure if my we're loosing our minds, or if AutoDesk fixed something somewhere. Seriously starting to doubt my sanity, but myself and three coworkers have been battling this issue for the last 5 months.

Regardless, this issue has mysteriously evaporated. Guess I'll table this issue until it shows up again.

[payam.rad]

Any resolution on this? I am having a somewhat similar issue with Linked CADs. 

[RobDraw]

The thread is marked as solved and the OP is no longer having the problem. It sounds like an update may have fixed it but it's impossible to say how it went away.

[challstrom]

RobDraw is correct. After fighting with the issue for what felt like forever the problem disappeared. The only reason I'm sure I'm still sane is that there were several of us trying to troubleshoot it on our end.

Still think AutoDesk snuck in one evening and did  some sort of fix/correction. 😆

I wish you the best, payam.rad. Only advice I can give you is to get a list of steps needed to recreate the issue. And make sure your CAD file is broken all the way down, with blocks and references exploded/imported.

[payam.rad]

thank you all.

What i am doing for the time being is to freeze the layer i don't need in CAD, bind all the xred files in CAD and then bring it to Revit, where I don't need to do a whole a lot in Revit. Seems to work, but i was hoping i could have. A way to update the new xref file and be done with it without having to go through clean up every single time we get a new CAD background. 

Thanks,

[ToanDN]

When you reload a CAD link, look at the box that says Retain graphic overrides, or something like that.

[payam.rad]

"Preserve graphic override"... yeah, it doesn't always work.

[challstrom]

Update:

You know it's bad when you google a Revit issue, and your own post shows up without a solution... Almost 2 years later to the day, I've ran into this problem again.  I'm running Revit 2024.2, but nothing much else seems to have changed.

Anyway, I'm having the same issue again. The "Preserve Graphic Override" checkbox doesn't seem to be working. I'm going through the troubleshooting steps again to see if there's something I'm overlooking, but not optimistic.

Wish me luck all!

[SteveKStafford]

This is the result of Revit failing to respect the Overlay vs Attached Xref conditions for DWG files. When a file is initially linked to a Revit model it will not display layers belonging to any Xref that file contains. However if you open the file in a new session of Revit, or someone else opens the Revit model, you'll find that the Xref layers are now visible too. The Xref layers include the vertical bar (|) in the layer name, for example IMPORT-Layer 01|A-Arch-Low...where IMPORT-Layer 01 is the XREF followed by the layer name.

You can mitigate this and turn off all the layers for Xrefs IF you can get whoever provides the DWG file to you to assign each XREF to a unique layer. In our case our Civil and Landscape disciplines assign all Xrefs to C-XREF or L-XREF. Our Revit project teams know to turn off those two layers to prevent XREF layers from showing up in any view with the DWG included. You should also find that the overrides you apply to native layers (not XREFs) will be maintained more reliably.

I wrote about this issue in 2020 on my blog: Blog post one and Blog Post Two

[challstrom]

@SteveKStafford  Your blog posts are informative, and I wish this was the issue.

The DWG we're currently having issues with doesn't have any Xrefs in it. They've all been imported as blocks and then bursted to avoid this exact issue, as well as saving the file as a DXF to remove some of the 3D elements.

I'm sure we could go into the DWG and clean it up, flattening the 3D elements, purging and auditing, cleaning up the layers, etc. This isn't feasible to do ever week or two as revised Architectural CADs are produced and sent to us.

[SteveKStafford]

Might try leaving them as Xrefs then, assigned to a unique layer you can turn off. In some sense an Xref is just a clever block. So binding an Xref is still a nested element that Revit knows has layers in it. The issue I wrote about is layers being shown that shouldn't be at all.

Ideally you shouldn't alter their file other than turning off layers via V/G. I have seen V/G settings change when a DWG file is reloaded after it has had new layers introduced. In my testing I've not been able to reproduce it though.

[eschellEJ4JQ]

I am also having this issue when linking in live Civil dwgs. I can't even get it to reliably go right or wrong. Some reloads of the arch model (containing the dwg) look fine, others revert layers back on. This is in 2022.1.5 but I have not been able to find a solution either.

[zlange8AJCE]

It sounds like you have already incorporated this variable into the mix but just sharing a finding. It seems that when you apply a view template to a view, It will turn all layers of the "imported" category on. i.e.

-If I have no templated assigned and I completely clean up my .dwg in CAD then link. My frozen layers are all off, but imported and able to be toggled on at a later date. 

-If I have a template assigned and I link the same file, my frozen layers wont physically show in view (see snip) but in the template, they are all turned on. 

Visibility Graphics Window:

View Template Window:

So on the first insert your CAD plan might look ok but as soon as you change view templates every layers gets turned back on. Unless you have the layers to control/turn off saved to the view template.