GlScene is far from dead, in fact development is more active right now than it has been for quite some time. They've pretty much finalized Lazarus support, included direct support for Newton Dynamics (a physics engine).

The latest reccomened release (http://sourceforge.net/projects/glscene/files/) is from this very month, I'm going to be investigating it in great detail, Cast II (http://www.casteng.com/) and GLScene are two of the most game ready 3D environments currently available for Delphi, FreePascal/Lazarus.

I strongly advise learning the basics of GLScene, when you grasp it's design you'll find it very easy to prototype all kinds of ideas. It's also an excellent tool to help understand the advantages an object orientated design can give you in terms of flexiblity