There is no simple process I found.
Here is what I do.
1. I first generate a 3D of my PCB,
2. Then I load that 3D Step file into a 3D viewer or editor,
3. View the side I need and grab a picture of the screen,
4. The resulting picture must be converted to monochrome,
5. Send the file to Online image vectorizer ,
Of course, chosse "DXF" as the required output from conversion.