Export to FBX rotates the coordinate system

_andrew_roth_ — Wed, 12 Mar 2025 18:44:12 GMT

I was pulling meshes from Navisworks Manage to Fusion, converting to CAD, then using that as reference data in Inventor. When pushing the inventor component back into the Navisworks model, the position was way off.

I was a little confused, and and found a few posts that I think are referencing similar issues.
https://forums.autodesk.com/t5/navisworks-forum/fbx-export-problems/m-p/7469434
https://forums.autodesk.com/t5/navisworks-forum/fbx-export-navisworks-2023/m-p/11256126

To make the issue easier to follow I model a UCS (triad) in Inventor that matched the model Coordinates.

I opened that with Navisworks, and the orientation matched.

When I open the FBX file in Fusion the coordinate system seems to be rotated about the Z axis.

Using the 'Right Hand Rule', we know the model has been rotated +90Deg around Z.

I checked the file options in Navisworks, and the up Orientation is set to Z, changing this to Y had no effect on the exported model orientation (as expected).

However, changing the North direction in the Navisworks File Options to X cased the model to rotate about x 90 and y 180, or some other combo, to get Y as the up direction?

I tired a bunch of combination of these values and none of them resulted in matching coordinates. (UZ,N-X UY,NX, UX,NY UY,NZ...)

Ok, fine. I'll just transform the model in Navisworks -90Z prior to the export. Also, I think the directions could use labels in this editor.

Nope, got this. 🤔

Clearly the coordinate system embedded int the FBX file is something that fusion is interpreting differently. I also tried using the other versions and ASCII type of FBX on export.

I think I'll just need to rotate the model in Fusion before continuing my workflow in the future as a workaround.

Any ideas what might be happening?

Software Versions;

Re: Export to FBX rotates the coordinate system

_andrew_roth_ — Thu, 13 Mar 2025 15:57:35 GMT

Here is a fix for anyone that comes across this.

If you export the FBX using the ASCII format, you can modify the file using Notepad.

Understanding the Current Settings

From your FBX file:

P: "UpAxis", "int", "Integer", "",0 P: "UpAxisSign", "int", "Integer", "",1 P: "FrontAxis", "int", "Integer", "",2 P: "FrontAxisSign", "int", "Integer", "",1 P: "CoordAxis", "int", "Integer", "",1 P: "CoordAxisSign", "int", "Integer", "",-1

UpAxis = 0 → X is the up axis.
FrontAxis = 2 → Z is the forward axis.
CoordAxis = 1 → Y is the right axis.
CoordAxisSign = -1 → Left-handed system (opposite of right-handed).
OriginalUpAxis = -1 → Unknown or unset.

How to Fix the Rotation

Since Fusion 360 expects Y as Up (UpAxis = 1, FrontAxis = 2, Right-Handed Coord System), update these lines:

Change to Fusion’s Expected Orientation (Y-Up)

Modify the file as follows:

P: "UpAxis", "int", "Integer", "",1 P: "UpAxisSign", "int", "Integer", "",1 P: "FrontAxis", "int", "Integer", "",2 P: "FrontAxisSign", "int", "Integer", "",1 P: "CoordAxis", "int", "Integer", "",0 P: "CoordAxisSign", "int", "Integer", "",1 P: "OriginalUpAxis", "int", "Integer", "",1 P: "OriginalUpAxisSign", "int", "Integer", "",1

Explanation of Fix:

UpAxis = 1 → Y-up (instead of X-up).
FrontAxis = 2 → Z-forward (keeps front facing correctly).
CoordAxis = 0 → X is right.
CoordAxisSign = 1 → Right-handed coordinate system (Fusion 360 default).
OriginalUpAxis = 1 → Helps some software interpret the correct original orientation.

Next Steps

Edit the FBX file in a text editor (Notepad++, VS Code, etc.).
Save the changes.
Reimport into Fusion 360 and check the orientation.

This should correct the +90° Z rotation issue.

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Export to FBX rotates the coordinate system

Re: Export to FBX rotates the coordinate system