It's been a long time and I have a lot more experience but haven't actually used pieces of cake to make the full picture in a while. the last time I did this the ended up seperating. I used icing inbetween. I wonder if it was because of the icing i used (store bought) I make buttercream now and ofcourse is awesome just wanted to know if any body used dowels or anything-it is a one layer cake that I will be shaping from seperate pieces to get the entire object. TIA

The only thing I can think of is to make sure whatever board you use is very sturdy and doesn't have any "give" to it so that it could cause the cake pieces to separate.

what shape are you trying to put together ?