Units error on exported DXF file

[Juha.Kuusama]

I exported parts from another CAD software as step files. Fusion read those in ok. Units were in cm’s. Strange but ok, as measurement were correct. For example, the attached part large hole in the middle is reported as 2.22cm diameter. I generated DXFs by creating a sketch on a face and saving the sketch as DXF. Opening the DXF in Fusion 360, the middle hole is correctly reported as 22.20mm. I sent the DXFs to my manufacturer, who reported that AutoCAD 2023 says files are ten times too small (middle hole 2.22mm).

The manufacturer was able to fix the scaling, so production was not disturbed. I'd like to know if changing the document dimensions in the step file fixes the issue; in other words, are my step files safe for further development? What is a safe method to use step files in order to avoid dimension errors in general?

[TheCADWhisperer]

---

@Juha.Kuusama wrote:

 For example, the attached part... 

---

@Juha.Kuusama 

No file Attached?

Attach the original STEP file.

Attach the resulting *.f3d file.

Attach the resulting *.dxf file.

[Juha.Kuusama]

They were shown in the original post? I'll try again:

[Juha.Kuusama]

Now the attach worked. Apparently, I attached another part that I referred to in the first post and the hole in this is 23mm. Anyway, the issue is the same.

[TheCADWhisperer]

I do not see your *.f3d file?

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[Juha.Kuusama]

Sorry, I'm slow today. (But you could have opened the step yourself to get this. 🙂 )

[TheCADWhisperer · Accepted solution]

---

@Juha.Kuusama wrote:

 (But you could have opened the step yourself to get this. 🙂 )

---

At 65 years of age - I have learned to never trust anything that someone else tells me - I trust the geometry.

Your *.f3d file that you attached does not have a proper sketch.

But that isn't the problem.

The problem is that the dxf file isn't "units aware", that is, it doesn't know what units it is supposed to be so it will open as whatever units the destination has as their default.

1. You can change the document units in Fusion 360, but that is only one half the issue.

2. The second half of the issue is what is the default unit setting for documents at the destination.

In this case the destination AutoCAD users did not need to scale anything - they merely needed to run the -dwgunits command and change the document units to Centimeters (4).  Very few AutoCAD users know about this command.

[Juha.Kuusama]

> The problem is that the dxf file isn't "units aware"

Oh. I had no idea. Somehow I took it for granted that the world most used CAD format would include the most basic design parameter. Live and learn. Thank you!

[Phil.E]

File>Export should provide the active document units for the exported document now. 

How to update Fusion