Hm I don’t know these other tools well but if the trend is FOOS is growing in 3D modeling, I don’t see why 360 couldn’t be seen as heading off that threat
The best open source 3d modeling tool is blender but its not a great solid modelling tool. Fusion 360 is a solid modelling CAD/CAM program aimed for 3d printing/milling. The open source scene there is pretty bad.
To echo LegitShady, FreeCAD is the only open source tool that even aspires to be anything like Fusion 360. Blender is essentially unusable for precise modeling since it doesn't have a constraints engine or a proper history. For example, you can't (easily) draw a 2D sketch of a rectangle with 5mm fillets, extrude that into a cuboid, drill a hole in it, then go back later and change the rectangle dimensions or the size of the fillets.
