3D Scanning and Printing

Celestial Feat

During a visit at the National Palace Museum in Taipei I discovered the art piece Celestial Feat (仙工). It’s an intricate ball with 21 concentric layers carved out of ivory. I thought to carve this out (i.e. make substractively) was a wonder and served as inspiration for my assignment.

A video posted by Raphael Schaad (@raphaelschaad) on

Approximating intricate details on outermost sphere of ivory ball by cutting a sphere from the complex stock Antimony volume Gyroid, a trick I saw Albert Chen doing with a Schwarz Diamond.

Incorporating custom supports in the design (and consequently turning automatic generation of supports off during toolpathing) was the only way I was able to successfully print these complex nested shapes.

Puzzle Star Cube

While backpacking through northern Thailand I bought a bamboo wood puzzle from an artisan.

Make your own by fabricating (3D printing, CNC milling, casting, …) this part (.obj) 6x.

3D Printers in the Shop

Currently we have two well working Ultimakers 2. They can print without support structures. If they print support structures, they are printed with the same material. Then we have two bigger machines from Stratasys (Dimension Elite in the corner and Objet Eden260VS by the door) that always print support structures and do so with a different material that then gets removed with WaterWorks detergent in the Stratasys ultrasonic cleaner, which is located next to the electronics shop. To print on those we email an .stl to Tom (3dprint@cba.mit.edu). We also have a Form 1 but resin printers are messy and it’s currently not working.

Meshes should be more or less watertight, printers will usually be graceful about slightly open meshes though.

Characterizing a 3D Printer

It’s good to characterize a machine by printing a piece that is designed to test:

Cura for Ultimaker

Printing Material

PLA is the easiest and warps the least due to its low extrusion temperature. It also has great adherence and doesn’t require glue stick on the platform. For CPE and ABS applying some glue with a moist paper towel to the platform can be beneficial. I couldn’t find what CPE stands for, but it seems UM internal lingo and was formerly known as U-PET.

Filament comparions guides by MatterHackers and Nick Lievendag.

Outlook

3D Printing by Raphael on Pinterest

Portrait

I asked Eric to scan a portrait of me with the Sense connected to the Windows workstation (MAS863/FabClass15). It often lost tracking and the resuling model was bad. I then mounted the Sense on a selfie stick and turned myself on a rotating chair. I asked Ali to adjust the height and angle of the Sense while I was doing three consecuitive turns. The resulting scan was better.

I used the cut, fill, and retouch tool in the scanning software to improve the model.

I exported the model as .obj, .ply, and .stl.

To view the model on my Mac, I first tried the free Autodesk FBX Review from the Mac App Store. Unfortunately it didnʼt display the color.

We also have the stationary NextEngine 3D scanner hooked to another Windows workstation (MAS863/FabClass15) with the software ScanStudio. This scanner might be better for small objects.

123D Catch

This iPhone app creates some impressive results. Here’s my public 123D profile with viewable and downloadable models of the scans. The viewer to embed models in websites is poor (design, interactivity, initial viewport) and there’s better solutions for that (see below).

When capturing the scene it’s counterintuitively better to not have a flat white background but instead have a background with texture. If you think about it some more it makes sense. Just like a computer mouse, there needs to be background information to track.

I imported the resulting models in a newly created Sketchfab account, a platform that allows me to share 3D models for others to download and to view via an embeddable 3D model viewer. When exporting textured models from Rhino, you need to import the .mtl (material) file alongside the .obj (geometry) to Sketchfab. Rhino also exports a .png texture file, which must be uploaded additionally in Sketchfab under Materials > Diffuse > Texture > Manage Textures > Import Texture. Rhino materials that don’t have a texture such as translucent plexiglas or glossy white plastic can be approximated well with Sketchfab’s material and light settings. Here’s my public Sketchfab profile.

Portrait 3D Scan, using the Sense 3D scanner

Portrait 3D Scan (of the 3D printed Portrait), using the 1234D Catch iPhone app

Design Recitation

There’s a lot of implicit design in this class. Justin A. Lavallee and Nathan Melenbrink offer approaching the class with a design process and/or design crits (critiques) in a studio environment.