Tekla Structures BIM Software - Open approach to Building Information Modeling
Unity - The multiplatform game creation tools for everyone.
BIM Vision - Freeware IFC model viewer.
Godot Engine - Feature-packed 2D and 3D open source game engine.
FZKViewer - FZKViewer visualises the sematic data models IFC, CityGML und gbXML
Blender - Blender is the open source, cross platform suite of tools for 3D creation.