Warning!!! ABS and PLA do not mix well with open flames! Note the melted fingers in this picture! If you plan to use candles in your sculpture, be extremely cautious and don't come crying to me when you burn down the entire world because of your silly art project!
So we've all seen busts made from 3D scans, but since 3D printing makes it so easy to add precise custom features, why don't we step things up a notch by adding some LED and candle lighting. The original plan was to have red LEDs coming out of the eyes and candles protruding from the hands, making the bust look like an evil mage, but the candles didn't end up working so well and I only used them for a quick photoshoot, seen above.
Here follows some lessons I learned while creating this sculpture, from scanning, to model editing, to printing and final assembly.
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Step 1: Find the Tools and Get 3D Scanned
I spent an afternoon with some friends at the local FabLab in Chicago. We used an Xbox Kinect and Reconstructme for 3D scanning. This print was done at my workplace (the School of the Art Institute in Chicago) where we have a Stratasys Dimension 1200es. You can get similar results with a desktop FDM which should be much easier to find, or you can go all out and get your model printed by Shapeways, in which case you won't have to worry about overhang and you'll have more materials to chose from.
There are countless guides on 3D scanning with an Xbox Kinect. You can do it yourself with an office chair, or have a steady-handed friend walk around you. Here are some tips:
Choose an interesting pose!
If you have access to a 3D printer which uses dissolvable support material, your options are less constrained. If you only have access to printers with breakaway support material, you may want to limit overhangs
It's easy to accidentally track the scanner with your head. This will mess up the model, so make like a statue.
Step 2: Repair Your File and Add Features
The STL file created by your 3D scanning software will likely have discontinuities in the mesh which we'll need to fix before we can edit and print.
I used NetFabb and Geomagic. You can find a free version of Netfabb here. If you don't want to install any software, try NetFabb Cloud, which apparently is now hosted by Microsoft… weird… whatever. There is also an amusing website called Will It 3D Print which is both useful and self-explanatory.
Now that your mesh is solid, we can add features like holes for LEDs/candles, and a base so that the bust is nice and stable.
I used Rhinoceros for these manipulations, but you could also use Tinkercad (great for beginners but has a limit on polygon count for STL import) or whatever 3D modeling program you prefer. You just need to import your 3D scanned mesh (an STL file) and performa few boolean operations.
Understanding Boolean Operations
Boolean operations are simply ways to create a new 3D object out of separate 3D objects by adding, subtracting, or splitting them at their areas of intersection. It might be helpful to think of a Venn diagram, but applied to a 3D model.
How to do it in Rhino or Tinkercad
After importing the repaired STL into Rhino and scaling it to the size I wanted, I had a few simple things to model before I could execute the boolean operations.
First, I modeled the base by drawing a polygon and extruding it at an angle. Then I lined the base up with the scan and joined them using 'MeshBooleanUnion', which in Tinkercad is simply called 'group'. Then I modeled a sphere, stretched it into a prolate spheroid and intersected it with the back of the head, creating a cavity which would allow me to install the LEDs and a coin cell battery. Finally, I created cylinders that matched the circumference of my LEDs & birthday candles (which, funnily enough were both 5mm), carefully intersected them with the eyes and hands, and subtracted them from the mesh. Both of these subtractions were done using 'MeshBooleanDifference', which can be achieved in Tinkercad by selecting the cylinders and spheroid as 'holes' and then grouping them with the scanned mesh.
Now we're ready to export the model as an STL and print it!
Step 3: Print and Assemble
As I mentioned before, I was lucky enough to have access to a Stratasys Dimension 1200es which uses dissolvable support material. The brownish stuff you see in the picture dissolves when the part is submerged in a sodium hydroxide solution for several hours.
If the printer you're using can't do this, you can still generate breakaway support structures for areas with overhang, but you'll have to remove it manually and then spend some time deburring your part. This is why it's good to keep this in mind when selecting a pose to scan.
My original plan was to have fire coming out of the hands and red LED eyes. The opening in the head is big enough to accommodate resistors and a small battery. As mentioned in the intro, open flames near ABS is a terrible idea. I just had the lit candles installed long enough for a quick photo shoot, then I stuck with the LEDs. See how they glow!