usBIM.viewer+ is described as 'Do you need to open an IFC file and modify it?' and is an app in the Office & Productivity category. There are four alternatives to usBIM.viewer+ for Windows, Mac and Online / Web-based. The best alternative is Online 3D Viewer, which is both free and Open Source. Other great apps like usBIM.viewer+ are FZKViewer (Free), Solibri Model Viewer (Free) and BIM Vision (Free).
Solibri Model Viewer (SMV) is the software that everyone should use within the construction industry. It’s free of charge and allows you to open all Standard IFC and Solibri Model Checker Files. Transparency is given on open issues and challenges.
Freeware IFC model viewer. It allows to view the virtual models coming from CAD systems like Revit, Archicad, Advance, DDS CAD, Tekla, Nemetschek VectorWorks, Bentley, and others without necessity of having commercial licenses of these systems.