I really could not find a straight forward tutorial for exporting to DXF from Autodesk Inventor 2019, so I am making my own Note to self.

In Part view, right click object and select Create Drawing View.

Since we use sensible scales and values in Norway, pick ANSI (mm) as template.

Click the FRONT side, to get the correct view from the top. Then click OK, it doesn’t matter where the object is located.

Go to Save As, then Save Copy As.

Pick a filename and click Options.

Enable Customize DWG/DXF, and pick the FlatPattern.xml, click Next.

Change data scaling to Full Scale (1:1) and Closest to AutoCAD Mapping. Click Done and Save the file.

Find your saved DXF file, and check it in a different DXF viewer, like Autodesk DWG Trueview 2019.

Below we can see the 2D result of your 3D project. Use the Measure to check some points if it correctly in scale.

This model is 1555 mm in length, and thats exactly what I measure. 1:1 spot on!