Archive 2015: 3D printed model-kit with press-and-fit properties

Searching for ways to produce multiple parts at once

The brief:
Create a gift in a gift box. The gift needs to contain a miniature version of a custom made bus,
Not intended for mass production, but more or less around 50 unique pieces should be made.
We had the idea to create a gift box with a “model-kit for assembly” type of thing.
The minibus parts would be presented in a way it is often done with scale models. All parts connected in one bigger part, ready for break out and assembly.
We considered a 3D printed solution. Another way to go was using the “mold and casting” technique, also, in that case, we would need a prototype or master.
Soon I realized during the design process that I faced the following 3D print/design challenges:

1. make parts thin enough so they hold, but can break with a slight turn.
2. make the parts so they can be assembled, with a simple “press-and-fit”, and don’t fall apart.
3. is there a way we can stack the model-kit frame so we can produce more in one print run?
In the first print run, we failed at challenges 1 and 3.
Challenge 2 was a success!
I used little ribbons on the parts to create just enough friction so the parts can hold when you “press-and-fit” the parts during assembly.
Challenge 1 we can fix, it’s a matter of adjusting the thickness of the design.
Challenge 3 needs a solution, stacking the design is no option, the model becomes complicated and needs too many supports.