STL Export Scaling Issue

[sozoroski]

When I export a model to an STL file it seems to change the units from inches to centimeters. Then when I go to open up the STL file the units display inches (like it should) but scaled as if it were converted to centimeters first. For example, a part with a 10in diameter would show 25.4in diameter on the exported file. I have checked my document settings and export settings to ensure both are set to inches (they are). Does anyone have any idea why this is happening? 

I am running Inventor Professional 2021

[TheCADWhisperer]

Can you Attach *.ipt and resulting *.stl file here?

[mcgyvr]

Where are you opening this STL file?

What units is that program expecting?

My first guess is that you are modeling in inches and may have your stl options (options button next to the save button while exporting) but your program (maybe 3d printer program) is expecting different units..

You need to have your export options set to the units your opening program is expecting or set that program to open the file in the same units you exported with..

I model in inches.. set my export options to mm as my 3d printer software expects mm.

A stl file is unitless so it doesn't pass the desired units in the actual file.. 

[sozoroski]

I am opening the stl file in Inventor and it still shows the scaled up dimensions (even with document units set to inches). Does inventor expect different units than what is set in the document settings when opening an stl file?

[mcgyvr]

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@sozoroski wrote:

I am opening the stl file in Inventor and it still shows the scaled up dimensions (even with document units set to inches). Does inventor expect different units than what is set in the document settings when opening an stl file?

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Just like when exporting you have the "options" button right next to the open button.. Press that and select the proper units.

Do not confuse that with the document units.

[sozoroski]

I cant upload the file I was working on but I did a test with a 1" diameter cylinder and got the same results. I attached the stl and ipt files. Very clearly shows that it converts to centimeters and just slaps on inches as the unit.

[sozoroski]

I have the proper units set for the export settings as well. That is why I am stumped. The document settings are in inches, when I export and hit options the units are set to inches there as well.

[mcgyvr]

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@sozoroski wrote:

I have the proper units set for the export settings as well. That is why I am stumped. The document settings are in inches, when I export and hit options the units are set to inches there as well.

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You need to set the correct units when you Open.. In the open dialog there is an options button just like when you export that you need to press and set the correct units. 

[sozoroski]

When I go to the open options, the units are set to "template units" which is inches. I switched it to "inch" just to be sure and it still opens at 2.54x the expected dimensions

[sozoroski]

I've been using a work around by just direct editing the entire part and scaling it to 0.3937 the original size so when it exports it, it is at the correct dimensions. I would love to learn why it's doing that or what I am doing wrong but I have gone through every setting that I think could apply to the export but still no change in the final result. It seems that when I export the part it automatically scales it to centimeters despite what I have set in the export/document/opening settings.

[mcgyvr]

You don't seem to be setting the correct units on export.

I have no problems opening your ipt file, doing an export (ensuring to set the options units to inch) and opening it back up (setting options units to inch).. It retains the proper scale..

If you are positive you are doing this please post a screencast of the entire process.. 

https://knowledge.autodesk.com/community/screencast

[sozoroski]

Let me know if I'm doing something wrong!

https://autode.sk/3lkkulR

0475ccdc-341e-4456-a73c-6b09026ffb76,640,620

[mcgyvr]

You've got it right from what I saw.. But Inventor isn't working properly for you there..

What version of Inventor are you using? including updates..

Please open the stl file I attached above.. Does that open up to be a 1" circle?

[sozoroski]

The file you attached opened fine and displayed the correct units.

I am using inventor professional 2021 64 bit edition. Build 183. I do see that there is an update and hotfix released a month ago. I'll download those and see if the issue was resolved with the update. If not I'll send in a bug report.

Thanks for the help mcgyvr!

[mcgyvr]

You may want to try the Inventor Reset Utility to reset your user profile..

(Export your application options first)

I have build 183 too installed now and have no problems exporting to the correct size.. 

[sozoroski]

Are you using inventor 2021? The file you attached had 2020 in the name.

[sozoroski · Accepted solution]

I updated my inventor and installed the hotfix and it seemed to have solved the issue. Thanks for the help!