We are in the process of developing a Qt-based GUI framework for CAD kind of applications that provide a full integration of OpenGL and Direct3D rendering using plugin architecture.

The framework is highly customizable to our clients needs.

Currently it offers the following:

Multiple views embeddable through the Designer. You can place a rendering canvas on a form, dialog, using the Designer or code.

Rendering calls are abstracted from the main application logic. The entire rendering engine is highly extensible. Switching APIs (OpenGL or D3D) is a matter of one liner.

Supports of editable 2D and 3D vierws, where a canvas can be assigned a different view type dynamically.

This framework requires licensing. If you are interested please let me know.