BricsCAD is the modern CAD alternative. It is based on DWG, and it is compatible with everything you know. BricsCAD is available as a perpetual license that you can buy once and use forever.
Other BricsCAD® Products
Go from concept to detailed construction documents in one 3D workflow.
A complete mechanical design toolkit, all in .dwg. Assemble freely using the power of 3D Direct Modeling.
Collaborate effectively throughout design and construction.