GTK - GTK+ is a multi-platform toolkit for creating graphical user interfaces.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
PyQt - Riverbank | Software | PyQt | What is PyQt?
Autodesk 3DS Max - 3ds Max is software for 3D modeling, animation, rendering, and visualization. Create stunning game enrivonments, design visualizations, and virtual reality experiences.
wxWidgets - wxWidgets: Cross-Platform GUI Library
ZBrush - ZBrush is a digital sculpting and painting software solution.