PrintTalk - a constraint-based imperative DSL for 3D printing.

We present PrintTalk, a DSL to "program" 3D objects, called "gadgets". PrintTalk also features "topologies", which are predefined spacial arrangements of gadgets. Gadgets are composed by executing a gadget script (possibly consisting of subscripts) that 'draws' the gadget in the 3D scene. However, executing the script also returns a number of constraint variables. These variables can be constrained inside the gadget and can also be bound outside the gadget in order to constrain the produced gadgets after the facts. This is the essence of the gadget composition mechanism of PrintTalk. PrintTalk is implemented in DrRacket. Running a PrintTalk program generates a file that is sent to the 3D printer. We validate PrintTalk qualitatively by comparing the code for complex gadgets with the code needed to print those gadgets in existing languages.