Sunday, November 1, 2009

How to Print Your Own Model

Whew, that was a pain.

The whole fun of the Makerbot is in making your own drawings of some 3D object, then making a print from that model. For Makerbot, this requires using a 3D drawing program, then feeding the result into a program called Skeinforge that decides where plastic needs to be squirted out. It's not the most straightforward process, and the tools are a bit cryptic, but I can at least say I've now done it.

The model I chose was pretty simple - a two foot high glazed pot - that I'd drawn when we were playing around with ideas for landscape work in our backyard. It seemed simple enough to make a decent model. I exported it as a DS3 file from SketchUp Pro, read it into Blender, exported it from there as an STL file, and went into Skeinforge.

Skeinforge is an open-source program intended mostly for scripting; if you run it, you get a window with twenty buttons, but most of those buttons are either settings or only run one particular pass on your file. I finally figured out to press "Carve" to convert the STL file into an SVG file that broke up each layer of the drawing, then pressed Export to save out the GCode file that the Makerbot will actually print. I also figured out I could do this from the command line:

# This takes in the stl file, and generates a SVG file with the same name,
# but with _carve appended and
python skeinforge_tools/ myFile.stl
# This command takes in the _carve file, and generates the GCode.
python skeinforge_tools/ myFile_carve.svg

I made two versions of the model - an inch-tall pot, and a three-inch tall pot. This picture shows how the one-inch pot looks. Both pots are going to my mother-in-law for her half-inch-scale dollhouse.

This picture shows a couple of the aborted attempts to do a three inch tall pot. In one case, I stopped the print job because it was late, and in the other two, the Makerbot hung about 20 minutes into the print. These do nicely show the interior structure that Skeinforge uses to fill interior areas. Skeinforge allows both a grid fill (20% solid), and a hexagon fill (here 10% solid).