DWG Links/Imports and Model clutter

[d.gencheva]

Hi all,

Recently I have been testing how links and imports affect my models. 

In the majority of articles I have read online they state that Linking is preferred due to the large amount of line patterns, materials etc which are brought into the model with an Imported DWG. However, links seemed to bring the exact same amount of clutter as the imports did in the files I tested.

The articles also state that imports generally result in a larger file size, but this Autodesk article states the opposite What is the difference of importing versus linking a DWG file in Revit

In this case, I suppose the only drawback of imports in terms of Model health is that they are not as easily found in the models? How do you typically incorporate imports into your workflow? 

[SteveKStafford]

In AutoCAD speak an Import is similar to a block and a link is similar to an External Reference (XREF). An import cannot be updated when changes occur to it. It has to be replaced. A link can be updated easily. Until 2026 it was not easy to find out where imported CAD files are located but the 2026 release has been displaying imports too. Both introduce additional imported categories to display line weight, patterns and colors. An Import can be exploded (a link cannot) which will also introduced fill patterns and text styles based on the CAD file. Generally a link is considered superior to an import, especially if it will change throughout the project.

[d.gencheva]

I do understand the difference where a link can be updated whereas an import cannot, but in the cases where we assume that the DWG will not change once it's loaded in I am trying to understand why would a link would be still the better way to go about it, especially since 2026 displays imports too, as you mentioned above.

Asking just because everywhere I read about that Imports are considered very bad practice. 

[RSomppi]

Basically, when a .dwg link is removed, all the associated stuff goes away with it. That does not happen with imports, even if everything is deleted.

Revit used to be very poor with handling imports and file bloat was common. That "very bad practice" is kind of a leftover from those days when a lot of companies were making the transition from AutoCAD to Revit and importing was a common thing. It's still preferable to link but importing isn't as quite as bad as it used to be.

[SteveKStafford]

Imports are regarded as a poorer choice primarily because they are not easily updated but also because they run the risk of people exploding them which causes a bit more CAD file pollution in the model than a link does.

[d.gencheva]

I actually tested this as well - all line patterns and materials that the Link brought stayed after I removed it.
The "back in the day" explanation makes sense!

[RSomppi]

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@d.gencheva wrote:

I actually tested this as well - all line patterns and materials that the Link brought stayed after I removed it.

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I said/thought they were deleted along with the link. I can't really test right now but will need to verify for myself, I could be wrong.

[SteveKStafford]

You should find the imported categories are removed if the link or import are removed from the model.

It's the exploding of an import that causes the CAD related elements to be created and persist in the model. Also if a partial explode is done then many artifacts of the CAD file can exist in the form of additional CAD import instances (blocks). The partial explode does a top level explode and block instances become unique CAD import elements. That means a single CAD file could multiply to many after a partial explode. I have encountered projects with many thousands of CAD import instances, most recently I ran into one with more than 14k.

So linking is more useful and safer because they can't be exploded.