The Inventor Toolmaker describes how to create new classes and how to customize existing classes in the Open Inventor Toolkit, an object-oriented toolkit used for interactive 3D graphics. This book is a companion to Open Inventor Mentor, 2nd Edition - Volume I, which describes how to write applications using the Open Inventor Toolkit.

There are several ways to extend the Inventor toolkit. The quickest way, and the only way available without using C++, is to use callback functions. Various classes, such as the SoCallback^{( C++ | Java | .NET )} and SoEventCallback^{( C++ | Java | .NET )} nodes and the SoCallbackAction^{( C++ | Java | .NET )}, support callbacks to add user-defined behavior. To truly extend the system, however, requires C++ subclassing, which is the subject of this book.

Many Inventor classes and member functions are labeled as SoEXTENDER, which means they are available to programmers who wish to extend the toolkit. Note that these classes and functions are not documented in the Open Inventor C++ Reference Manual. Refer to header files and this book for information on them.

Other classes and methods are labeled as SoINTERNAL. These are used solely within the Open Inventor library and should not be used in applications. The labels SoEXTENDER and SoINTERNAL are for documentation purposes only and are not checked by the compiler.