Here is the test project that shows the multi-form bug in Truevision 3D 6.2.

When you run this app, the main form has some check boxes: Daytime, Raining, and Snowing. If Daytime is unchecked then it will be nighttime, and if Raining and Snowing are both unchecked then it will be a clear day (or night!). 

Make a folder for these files in your TV3DSDK\VB\Tutorials\ folder, like so:

C:\TV3DSDK\VB\Tutorials\Multi-Form Test\(files).