CAD Links Changing Scale AFTER Reloading

[Anonymous]

Hello!

So heres the problem I am facing on a daily basis it seems. My company likes to link CAD files into drafting views for placement on sheets. Im trying to get them out of this practice but were not there yet. That being said, when changes are made in CAD and the link is reloaded in Revit, what appears to happen is the scale factor in the CAD DWG's type properties, JUMPS to 12.00000. Its always 12. I have to manually adjust it back to 1.00000 and its fine.

To make this even more maddening, it doesnt do it to all CAD links. Just some. I have tried everything I can think of to fix this. I am open to ideas. Thanks Revit community! 

[SteveKStafford]

Make sure the units are defined properly in the DWG file. If you link the file and it doesn't get the scale correct then it means that Revit isn't finding the information it needs to determine the correct scale.

I should add that I've never seen Revit change the units on a file that's already been linked. I've seen it change the DWG's orientation (rotation) but not import units.

[martinTstewart_Adsk · Accepted solution]

The only thing I might add to Steve's response is that you could compare the unit settings in one DWG that is working correctly to one that is not, to see what may be different. If any differences, change the settings to match the one that's working.

If my reply was helpful, please "Like" or click the "Accept Solution" button below (or both).

[Anonymous]

Thanks for your replies guys.

The units is not the problem. They are set the same way in both drawings. But this should have nothing to do with issue I am having. The CAD link changes scale to 12 in the TYPE PROPERTIES. See the capture shot in the original post above. It always changes to 12 from 1. Not all drawings do this but when it does, its random and I cant figure out what could be causing it. Revit changes the link from 1 to 12 by just hitting reload. The drawing doesnt change scales in CAD. 😞

[SteveKStafford]

Is it always the same files doing this? Which version of AutoCAD are they saved in? Which version of Revit is it happening in?

Regardless, I'd consider starting a support request to see if there a bug as appeared with regard to reload and/or reload from.

[Anonymous]

Is it always the same files doing this?

No. It is truly random as far as I can tell. 

Which version of AutoCAD are they saved in?

AutoCAD MEP 2019.

Which version of Revit is it happening in?

Revit 2018

None of this matters though because I have done this in other projects using different versions and still had the same issues. It is random and I cannot figure out what causes it. So I dont see how opening a bug report would help as its clearly been going on for years.

I agree that it could be something within CAD that is being copy/pasted from job to job but with it being so random, I just dont know where to begin.

[SteveKStafford]

It has not been happening to me for years...or ever for that matter. That doesn't prove anything except that something is causing it to happen to you and your projects and not the ones I've worked on. I don't work for one firm either so it isn't my little corner of the world in isolation.

That's no consolation...

Are you seeing this first hand? You actually do the reload and it changes size? It's one thing to have users reporting it to you and seeing it happen while you mash the buttons. I've had more than one occasion where a user swears Revit did something but it was just another user doing something and syncing their changes.

Clues...we need clues 🙂

[Anonymous]

Lol. Yes I seen it first hand. Im the BIM manager of my office so I was able to refresh a CAD link and see it immediately increase in scale to 12. Its very odd, I know. 

[Anonymous]

So when I originally tried this suggestion it didnt work. Today I further investigated it and found that setting the precision to 0 fixed the whole thing. I was able to replicate this 5 times. Thanks for the tip!

[NateBrush]

I would have thought .DWG units as well. I haven't had the scale issue, but I have had origin points and rotation reset.

Did you try purging the CAD file and changing the PROXYGRAPHICS setting? I have had both of those resolve some weird link issues. Maybe they will help with this one.

I wonder, too if saving the .dwg to an earlier file format might be worth trying. Maybe Revit 2018 is having trouble interpreting something in AutoCAD 2019 files.

[SteveKStafford]

What were the unit precision set to originally?

[Anonymous]

They were set to difference sizes. 1/16, 3/32, 1/8, etc. Evidently any use of the precision scale causes the problem.

[SteveKStafford]

I must be missing some details, it doesn't seem to matter in my testing. For my attempt to replicate this I set up four DWG files with a box, all the same size. Each file is assigned to different unit precision. I linked them, then added some lines so there was some change and saved them. Then I used Reload. The links import units were not altered.

There must be something unique to your files that I know nothing of that is causing it.

EDIT: I was using 2018...need to try again in 2019 AutoCAD...

[Anonymous]

I am having the same problem - absolutely maddening.

The Cad link changes scale and rotation every time it reloads. Other Cad links in the same file are fine. Units are correct in the Autocad drawing, which I have recreated by pasting selected drafting elements into a new clean purged file. 

[SteveKStafford]

Earlier I missed a reply that detailed the versions being used, for the member who started this thread. If you're using a newer version of AutoCAD and an older version of Revit it is probably necessary to make sure you save to an older DWG version, one that is older or equal to the Revit version you are using.

[michael.coviello]

@Anonymous    I see this thread is old,   Was there ever a solution to this problem?    If the problem is still happening, Please log a support case.

Along with all of the other suggestions, If you haven't already found a solution.

Are there any warnings in the model that related to 'Extents greater than 20 miles'?    I'm wondering if your Revit model is outside of Revit's limits.

If you search the journal file,  are there instances of:

Geometry in the file my.dwg has extents greater than 20 miles (33km). This may reduce reliability and result in undesirable graphic behavior. Click OK to continue, Cancel to exit import.

[Anonymous]

This CAD link scale thing is happening to me today. I have changed the precision to 0 in CAD but it has not worked in Revit.

Totally maddening.

[michael.coviello]

Hello @Anonymous 

If you compare the UNITS dialog box of a dwg which does not change,  to the one that did,  Are there any differences?  and does setting them to be equal resolve this issue?  If it does not, please create a support case and a Revit specialist will be happy to review.

https://knowledge.autodesk.com/customer-service/account-management/users-software/support-options