If this is your very first time programming 3D, this chapter is going to be a challenge. There's no way around it, but programming 3D involves a lot more than drawing in two dimensions.
Not only do you have an additional coordinate, but you also need to convert the 3D drawing into a 2D image that can be shown on the screen.
There are models, cameras, scenes, views, and much more that you usually don't need to understand for 2D programming. But even the smallest 3D program requires you to at least understand the basic concepts and know how they fit in the larger picture.
Luckily, there are many tutorials online to get started with 3D and ActionScript. For instance, the following link provides a good overview of the basics: http://www.flashmagazine.com/Tutorials/detail/flash_3d_basics/
In this chapter and the next, we will focus solely on Away3D (http://away3d.com/). This is one of the most popular and open source 3D libraries for ActionScript. We use only this library to keep the...