3D Print and Scan

Week 4

This week was split into two mini projects: (1) Design something a few centimeters big that couldn't be made using traditional subtractive methods and (2) 3D scan an object.

While digging around the lab for something fun to scan I found these awesome shaft bearings, which are commonly found in the trucks of skateboards.

So, I kicked off the week by drawing motorcycles, which was pretty much the only remaining logical choice at this point.

After nailing out a few ideas, I dove into Solidworks to do a rough draft so I could start thinking in 3-dimensions faster. What really helped save some time and make matching my vision easier was going into [Insert] > [Sketch Tools] > [Sketch Picture] which lets you place an image file on any plane so you can work from it 1:1

But, after playing around with the design for a while, I realized I was hitting a local maximum of "meh". I really wanted to push more towards a "low poly" effect and make the moto feel more aerodynamic and aggressive.

So I exported the current model as an STL and imported it into Cinema 4D where I've picked up a few tricks. Using the displacement deformer, the wind deformer, and then the polygon reduction deformer, I managed to get really close to what I had in mind.

And this is where my small nightmare started: getting the model back into Solidworks. By this point, I had an incoherent mesh with the whole nine yards: dirty geometry, non-manifold edges, random intersecting internal surfaces, and tons and tons of holes.

It turns out, there's no one-click solution that turns gross clumps of meshes into a watertight solid. After boats of trial and error, I finally got it work by:

  1. 1. Exporting the model as an STL, opening it in Meshlab, running a few hole repair tools for good-times sake, and then exporting it as an OBJ file.
  2. 2. Enabling the ScanTo3D stock plugin in Solidworks and importing it as a mesh. Ran the mesh-repair wizard finally exporting a giant bundle of facets, each as its own mixture surface lofts, sweeps, etc.
  3. 3. Now comes the painful part: one by one reviewing each of the 100+ surfaces, deleting the internal nonsense ones, knitting the good ones in pairs, and plugging each and every hole by hand connecting the vertices.
  4. 4. If you've done it right and Solidworks hasn't freaked out yet, then your last knit that ties the entire shell together completely closed should magically solve into a solid body.

Thankfully it was smooth sailing from there. I just needed to re-cut the holes for the shaft bearingsl, add some leaders that connect into axles, and split the whole part in half so that I can pop the wheels in post-printing.

Tom ran my part as a quick draft on the Makerbot before dropping it in the nicer Dimension printer and I realized my tolerences for the friction fitting parts were waaay too tight, so I snuck in a quick change before the final was printed.

In the meantime, he also threw it on the invision printer to see how it would fare. I still managed to break it in a few places trying to remove it from the tray and sticking it in the toaster to melt off the wax support material.

[insert final photo]

A final touch of WD-40 on the wheels and this thing's ready to zip off!

For the 3d-printing portion of the assignment, I thought I'd try and scan my trusty Mailchimp figurine. Thankfully it was designed with nice, soft features all painted in a pastel, matte paint so it's perfect for this.

I was sitting with Will while he was scanning his sunglasses shades using the Minolta scanner and we seemed to have a hard time getting the machine to autofocus onto the object.

Fortunately, I had none of those problems with this piece and the whole process of scanning was absolutely straightforward with all the auto-stitching being super spot on. Above is a rendered mesh of the raw output from the scanner. With just a few more deletions and patching, this should be ready to go!