September is the perfect time for making gifts, especially if you’re making them yourself. My experiment this week was to create a Houdini Digital Asset (HDA) that generates a personalized snowflake ornament.
The experiment was a prototype to see how far I could take Houdini for creating personalized, fabrication-ready assets. I used an L-system to generate the snowflake shape and added a parameter that lets me type in any text for the personalized area. For my first test, I used my family’s name — The Smiths.
Once I had a working HDA, I exported an STL file and was so excited that I drove to the library to get it 3D printed.
I had jumped the gun a little.
The person who runs the 3D printer at our library immediately spotted a few issues with my first attempt. First, the bars holding the name weren’t flush with the rest of the design — something I had simply overlooked in my excitement.
He also recommended making the back of the ornament completely flat. I had beveled both the front and back, but because the print is built up layer by layer from the print bed, a flat back gives it a better surface to start from.
Finally, he suggested checking the design to make sure all of the narrow sections were at least 2 mm wide.
So I went back home and worked on those issues.
The next morning, I went back into Houdini and worked through the fixes. I used a Clip node to flatten the back, making sure to fill the cut surface so the model stayed watertight. I thickened the PolyWire geometry that formed the snowflake, increased the depth in Z, and adjusted the bars around the name so their backs were flush with the rest of the design.
Back to the library I went. This time, it was deemed good enough for a test.
I was asked to choose an infill percentage—10%, 20%, or 30%—which controls how much material fills the interior of the print. He recommended 20% as a good starting point, so that’s what I chose.
After about ten minutes, my ornament was printed! Another five minutes for it to cool, and I had an actual object made from my Houdini setup.
The total cost: $1.
It was gray, though. The library uses each spool until it runs out, so I didn’t get to choose the color. For this print, I added a coat of gold acrylic paint—and finally, it looked like the ornament I had imagined. Seeing the design move from an L-system in Houdini to a finished physical ornament was deeply satisfying. There are plenty of directions I could take the tool from here, but for this first version, three snowflake designs and one successfully printed ornament felt like the right place to call it finished.
