A three dimensional printing system comprising: a three dimensional print engine including: a vessel for containing photocurable resin including a transparent sheet at a lower end; a light engine for transmitting pixelated light up through the transparent sheet into the photocurable resin; a movement mechanism; a fluid processing station including a fluid injector port coupled to a fluid source; a fixture having a lower portion defining a lower face and a first fluid conduit coupled to the lower face; a transport mechanism; and a controller configured to: (a) position the lower face of the fixture in facing relation with the transparent sheet; (b) operate the three dimensional print engine including the light engine and the movement mechanism to form a three dimensional article of manufacture onto the lower face of the fixture, the three dimensional article of manufacture having an inside surface that defines an internal cavity, an inlet port that couples the internal cavity to the first fluid conduit of the fixture, and an exit port that couples the internal cavity to an external portion of the three dimensional article of manufacture; (c) operate the transport mechanism to transfer the fixture with the attached three dimensional article of manufacture to the fluid processing station; (d) couple the fluid injector port of the fluid processing station to the first fluid conduit of the fixture; (e) operate the fluid source to inject fluid out of the fluid injector port, through the first fluid conduit and the inlet port, and to the internal cavity. a three dimensional print engine including: a vessel for containing photocurable resin including a transparent sheet at a lower end; a light engine for transmitting pixelated light up through the transparent sheet into the photocurable resin; a movement mechanism; a vessel for containing photocurable resin including a transparent sheet at a lower end; a light engine for transmitting pixelated light up through the transparent sheet into the photocurable resin; a movement mechanism; a fluid processing station including a fluid injector port coupled to a fluid source; a fixture having a lower portion defining a lower face and a first fluid conduit coupled to the lower face; a transport mechanism; and a controller configured to: (a) position the lower face of the fixture in facing relation with the transparent sheet; (b) operate the three dimensional print engine including the light engine and the movement mechanism to form a three dimensional article of manufacture onto the lower face of the fixture, the three dimensional article of manufacture having an inside surface that defines an internal cavity, an inlet port that couples the internal cavity to the first fluid conduit of the fixture, and an exit port that couples the internal cavity to an external portion of the three dimensional article of manufacture; (c) operate the transport mechanism to transfer the fixture with the attached three dimensional article of manufacture to the fluid processing station; (d) couple the fluid injector port of the fluid processing station to the first fluid conduit of the fixture; (e) operate the fluid source to inject fluid out of the fluid injector port, through the first fluid conduit and the inlet port, and to the internal cavity. (a) position the lower face of the fixture in facing relation with the transparent sheet; (b) operate the three dimensional print engine including the light engine and the movement mechanism to form a three dimensional article of manufacture onto the lower face of the fixture, the three dimensional article of manufacture having an inside surface that defines an internal cavity, an inlet port that couples the internal cavity to the first fluid conduit of the fixture, and an exit port that couples the internal cavity to an external portion of the three dimensional article of manufacture; (c) operate the transport mechanism to transfer the fixture with the attached three dimensional article of manufacture to the fluid processing station; (d) couple the fluid injector port of the fluid processing station to the first fluid conduit of the fixture; (e) operate the fluid source to inject fluid out of the fluid injector port, through the first fluid conduit and the inlet port, and to the internal cavity.