Eric Powers (powerg@deltanet.com) wrote Apprentice, an Inventor “clone” distributed in source form. I asked him to describe Apprentice for us. Here is his response:
Practically every CGI/digital effects house that creates custom animation software has a need for developers who understand and use Inventor.
Apprentice serves as an extremely valuable learning tool by providing a free subset of Inventor to students and faculty with full source code so they can study, understand and make improvements to a popular framework. Many of the display, serialization and base classes are implemented and fully functional (such as NurbsSurface, Coordinate3, Texture2, GLRenderAction, Input/Output); much of the interactive and application support classes are not implemented (such as SoXtFullViewer, SoDragger). Apprentice is freely available for non-commercial, educational users, i.e., it is targeted for students, faculty and individuals with restrictions on use and distribution. Apprentice includes full C++ source code, cross-compatible with every system users have attempted to build it on. Apprentice works with OpenGL, Mesa, Motif, Windows, GNU C++ and MSVC++.
Apprentice is perfect for developers who want the basics and will be filling in the holes with their own code. Included with Apprentice is a quick example of a node that displays LSystems, a simple and concise example of how easy it is to implement a powerful class with minimal code.