Mayo is an open-source 3D CAD viewer and converter based on Open CASCADE Technology and Qt.
Users can view and convert 3D CAD files in different formats (STEP, IGES, mesh formats, …).
Mayo helps also user to graphically explore/analyze assembly trees and view properties (e.g. area, volume, ...).
Typical end-users are people working in design/manufacturing industry, either to use the software as is or customized through source code.
Mayo source code is distributed on GitHub with a permissive license allowing commercial and private use.