VPython 6, at vpython.org, is based on the cross-platform library wxPython. It improves VPython 5.74 and earlier by eliminating most platform-dependent code and by eliminating the threading associated with rendering.

The new version makes essential changes to the rate statement in VPython programs:

• rate is now required; an animation loop MUST contain it.
• rate still limits the number of loop iterations per second.
• rate now updates the 3D scene when appropriate, about 30 times per second.
• rate now handles mouse and keyboard events.
• If the animation loop is missing the rate statement, the scene will not be updated until and unless the animation loop is completed.

The heart of the user-interface code, creating windows and handling events, is the file site-packages/visual_common/create_display.py. It is imported by visual/init.py and by /vis/init.py; visual imports math and numpy for convenience whereas vis doesn't.

Please report issues to the Github repository, or to the VPython forum.