This is how you can use an STL (Mesh) for reference in Solid modeling, without the need to convert the Mesh in to solid.
More info on the tool here: https://help.autodesk.com/view/fusion...
0:00 Intro
1:00 Inser Mesh (STL)
1:40 Check Mesh warnings
2:15 Sketch Base
2:24 Extrude Base
3:30 Mesh Section Sketch
4:11 Edit Sketch
4:20 Fit Curves to Mesh Section
5:05 Extrude Cut
5:40 Section Analyzes
6:14 Scale in X and Y direction
7:00 Inspecting clearance