Open Inventor Frequently Asked Questions

Open Inventor Licensing

Open Inventor 2.0 represents the first release of Inventor that is licensed to third parties to run on other platforms (e.g., Sun, HP).

The Inventor Mentor and The Inventor Toolmaker

Since Open Inventor has been licensed to run on other platforms, the programming guides have been published and distributed by Addison-Wesley Publishing Company. The books are typically available through bookstores that offer a good technical book selection. The Inventor Mentor is volume I of the programming guide and describes the fundamentals of Inventor programming (ISBN 0-201-62495-8). The Inventor Toolmaker is volume II and provides advanced information for programmers who want to extend Inventor.

Automatic caching

Open Inventor supports intelligent, automatic caching on the parts of the database that are not changing. Previously, caching was either `on' or `off' (set at SoSeparator nodes). Inventor 2.0 supports a third setting, `auto'. This SIGNIFICANTLY improves performance and simplifies programming.

Error handling

Inventor now supports a formal error handling system. Note that the API was not affected by this change. All Inventor error messages are now posted to an SoError class. The application can supply its own error handlers, thus making it possible to route error messages to dialogs, as well as stderr or stdout. All handlers are called by the SoError::handleError() method. When debugging, you can set a breakpoint on this method to stop right before an error is handled.

Geometry primitives and SoCallbackAction

A new feature has been added to the generic Inventor traversal action, SoCallbackAction, that allows for shapes to return primitives (triangles, lines, points, normals, texture coords, etc.) describing the object.

Naming

Nodes, paths, and engines can have names (strings) associated with them. There are methods on SoBase::setName() and getName() to set/get names. To search for objects by name, see SoNode::getByName(), SoPath::getByName(), and SoEngine::getByName(). Also, the SoSearchAction can now search based on the name.

OpenGL rendering

Open Inventor 2.0 uses OpenGL for all rendering; there are no calls to Iris GL in Inventor 2.0. If you have written derived node classes in 1.0, the Iris GL code must be re-written to OpenGL.

Printing

Printing has been completely reimplemented using OpenGL rendering to an off-screen image. All rendering features can now be printed (e.g. textures and transparency).

Render Culling

Inventor now supports object level culling to the viewport. Culling, like caching, is controlled by SoSeparators.

Unknown nodes

Inventor 2.0 reads unrecognized node classes from file and attempts to use them. When an unknown class is read, Inventor will search for an accompanying DSO file and use it, (uses environment variable LD_LIBRARY_PATH to search for file classname.so) If none is found, an SoUnknownNode or SoUnknownEngine is created and used instead.

Inventor 2.0 also supports a special option for nodes called alternateRep. It can store a scene graph composed of standard Inventor nodes which will be rendered as a stand-in for your unrecognized node. During writing, the node or engine is written back out. Note that this mechanism works only with Inventor 2.0 files; unrecognized nodes in an Inventor 1.0 file will still generate a read error. This mechanism allows user subclassed nodes to be exportable, renderable, and re- usable.

SoEngine

A new class of objects used for animation and behavior. Engines are lightweight objects that are connected between nodes, the clock, and other engines to form interesting behaviorial objects (e.g. spinning windmill). Engines can be written to file along with the 3d scene.

Inventor programs that contain a lot of IRIS GL code or that made extensive use of Inventor subclassing will be more difficult to port, since they will have to be ported to OpenGL and since the internal structure of Inventor underwent some major changes.

IRIS Inventor Answers

What version of IRIS Inventor runs on which version of IRIX?

    IRIX     IRIS Inventor Version
  --------------------------------
   3.3.*   | (Inventor is not available for IRIX 3.*)
   4.0.*   | 1.0.1
   5.0.1   | (bad release... do not use)
   5.1.*   | 1.1.2
   5.2.*   | Open Inventor 2.0 (1.1.2 on VGX(T)/GT(X)/PI)

Will I be automatically upgraded to Open Inventor if I have IRIS Inventor?

Customers with software maintenance contracts that have purchased the Inventor 1.0 developer's option will receive the Inventor 2.0 developer's option when they receive IRIX 5.2.

Why do I get errors compiling the Inventor sample programs?

Inventor 1.0.1 requires C++ version 2.*. If you have C++ version 3.* installed on your system, you must specify the -v2 flag to compile Inventor programs. If you are using the Makefiles distributed with Inventor, you should change the line that looks like: LC++OPTS = +p -Wf,-XNp10000 to: LC++OPTS = -v2 +p -Wf,-XNp10000

Inventor 1.1.2 and Inventor 2.0 work with C++ 3.*; you must remove the -v2 flag from your Makefiles when you upgrade to those versions of Inventor.

If you receive this error when compiling:

"/usr/include/X11/X.h", line 44: error: Cursor declared as unsigned short [16] and XID You should rearrange the order in which you #include your files so that the Xt files are included before any file that references the IRIS GL include file. For example, be sure to #include <Inventor/SoXt.h> before <Inventor/nodes/SoTexture2.h>.