I am very interested in hearing from all of you who are using or implementing
3-D interactive applications what types of 3-D widgets you would
like to have in your applications.  

A 3-D widget is usually located in the same scene as other 3-D objects of the 
application.  It may let you

- manipulate application data, the camera,
  3-D objects in the scene and so on, or
- view the status of the application or 3-D objects
  via the widget's shape, color, position, orientation and so on, or
- do whatever I missed but you think is possible.

For example, a manipulative widget can be virtual trackball (shown as a
partially transparent sphere) super-imposed on the object to be rotated.
A feedback widget can be a ruler with ends anchored to 2 objects.  The length
of the ruler changes as the objects move and a numeric value is shown on the
ruler indicating the distance.  A widget can provide both manipulation and
feedback.  For example, the ruler can be used to change the distance between
the objects along its own axis.


Please e-mail me or post your opinions on 3-D interaction.  The information
I gathered will help me design a 3-D UI construction tool.
Your help is very much appreciated.