I want to create a game that uses a model for the game animations and 2D from the user interface and interactions.

In my render function I have tried

[pascal]Begin2D
Draw 2D things
End2D
Begin3D
Draw 3D models
End3D
Begin2D
Draw 2D things
End2D[/pascal]

The items in the first 2D drawing block as well as those in the second 2D drawing block are drawn in what looks like an alpha drawn state. I have tried to change the background behind them before drawing but it makes no difference.

How do I mix 2D and 3D things together?