I just had a client ask for a 3D Optimus Prime Semi. This means carving which I have only done once. I know I need to freeze the cake for easier carving, but not really sure where to start. I thought maybe starting with a 1/4 sheet cake and cutting in half length wise and stacking to start with. She needs it to serve at least 30. Any suggestions?

Aha! I found the perfect thing for you! A 62 set photo log of the building of an Optimus Prime cake!
If you click on each separate pic you get some instruction also
http://www.flickr.com/photos/floatingcat/sets/72157600493992206/

Shola...

Thank you very much. The instructions are in great detail unfortunately she wanted to "newest" optimus prime. Any other suggestions?