Hi!
I have started to look att the FLARToolkit to create Augmented Reality effects.
Downloaded the esamplefiles http://www.mikkoh.com/blog/wp-content/uploads/2008/12/learningflartoolkit.zip (this ones are with comments from the mikkoh blog)
The demo let you show a 3D-cube in pink. The code is easy to understand and worked instantly.
But hey, cubes are not fun! 
Were can I take the next step? I wnat to use Sketchup or another 3D-program with the FLARToolkit. My goal is to make my apartment in 3D and show it with FLARToolkit (The 3D moddeling is no problem).
Any suggestions? Plese give me a hint how to get started, been searching for houers now.
With Love
Ellie
