auto-scaling xref

[rkmcswain]

We have four drawings, one base and three xrefs. All four of them have the same settings for INSUNITS (2), and for AECDWGUNITSSETUP, as shown below.

Despite this, when we go to attach one of the xrefs, it insists on scaling the xref by 0.83333, as shown. There is nothing involved here that is defined in inches, all of these drawings are in feet. The only oddity is that the 3 xrefs were exported from ArcMap.

What other setting is controlling this?

@dgladfelter 

[dgladfelter]

What about your Civil 3D Drawing Settings?

[rkmcswain]

Apologies @dgladfelter - forgot to mention those are all the same, just as in your screenshot.

[Joe-Bouza]

Don’t know but recommend insunits=0 

[rkmcswain]

@Joe-Bouza  - Yeah, I know that, but many of our hundreds of users do not, or have forgotten, etc. What I'm trying to find out is WHY this is occurring in this situation, when all of the settings say that no scaling should be happening.  Thanks.

[AllenJessup]

Theoretically you shouldn't have this issue. However....

I'd recommend making that INSUNITSDEFSOURCE and INSUNITDEFTARGET are also set to 2.

[Anonymous]

Check dwgunits and make sure everything is as you expect.

[Anonymous]

dwgunits should summarize and set all of those insunit variables

[rkmcswain]

@jfmayo wrote:

Check dwgunits and make sure everything is as you expect.

Already have. That is the second image in the original post.

[rkmcswain]

Interesting enough, Autodesk support just told me to set INSUNITS to 0 in the parent drawing. So what is the point of INSUNITS matching in the parent and child drawings? 

I would really love to figure out what is going on here. I've made a couple of comments to your blog post @dgladfelter - but they have not shown up yet. Your comment there states that "AutoCAD does not apply any scaling when using INSERT or XREF provided Drawing A and Drawing B have the same units. " - which has been proven false here. For years, I've always said set INSUINTS to 0 in all cases, but I realize that in many cases, the users doesn't know or care about these settings, they just want to insert or xref drawings together without AutoCAD screwing things up.

Even more confused now, with Autodesk's support reply.

[Anonymous]

it's off by a factor of 12. I have been having issues with misbehaving blocks being off by a factor of 12 in PS. I don't know the answer to either of the issues.

I always set INSUNITS (from UNITS command) to unitless. I don't know if this solves your problem, but I do know that MAPIINSERTing an image with world file doesn't work unless the dwg insertion units are set to unitless.

[AllenJessup]

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@Anonymous wrote:

I do know that MAPIINSERTing an image with world file doesn't work unless the dwg insertion units are set to unitless.

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That's strange. I've never had that problem.

[rkmcswain]

I think we have a answer.

The child drawings I have were created with ESRI Arcmap. If I open the drawing, type in INSUNITS, and press enter , it says:

Command: INSUNITS
Enter new value for INSUNITS <2>:

So we can presume that INSUNITS cannot be blank, in other words, it must contain a value, right? We can also presume that the value reported to the user is the current value of the system variable. So based on that, you would agree that INSUNITS = 2 in this drawing.

So I close this drawing.

Then I reopen it, and do nothing except run the QSAVE command.

Then I Xref that newly saved version and the scale factor = 1.0, just like it should be.

So there is something about these .DWG files saved by ArcMap that AutoCAD doesn't understand, because it *looks* like INSUNITS = 2, but it does not behave like it until I resave the DWG file.

[Anonymous]

Excellent tech detective skills. You also jarred my memory free. I know I had the same issue but forgot to mention that i ran dwgunits in all references too. I did save a vendor dwg file in the wrong scaling and thought that was at issue. But the file did originate from either esri,  bentley or both. Both being more likely. Either way I thought acad should have inserted the vendor file correctly. I believe something changed either in 18 or 19 as we have worked with this vendors files often and have not had issues previously. My issue happened using 2019 maybe a yr ago.