3D printing and scanning

Task

Group assignment:

• Test the design rules for your 3D printer(s)
• Document your work on the group work page and reflect on your individual page what you learned about characteristics of your printer(s)

We have decided to take turns in doing the group assignment. I'm not on the roster for this week. The assignment is here

Individual assignment:

• Design and 3D print an object (small, few cm3, limited by printer time) that could not be easily made subtractively
• 3D scan an object (and optionally print it)

3D scanning

Skanect

Uses Kinect, a peripheral originally made for the XBox 360.

1. Plug in USB adapter.
2. Connect to computer.
3. Launch Skanect (important! only do this after plugging in the Kinect).
4. Scan, hit OK.

Revopoint

Commercial device. Software is called Revoscan.

1. Plug in.
2. Launch software
3. Scan, hit OK.

Open/Free Options For Photogrammetry

Round up

• Meshroom
  • Tutorial: Meshroom for Beginners
  • Tutorial: Meshroom for Beginners
• MicMac

Others

• Regard3D: open but complex, for advanced users.
• Sketchfab: 3D model repository.

Practical

We used the Revopoint to scan ourselves, but it was really fiddly. It was really hard to capture a full scan without having it lose track of where it was.

Finally we managed by going super slow and communicating all the time. One lesson learned is that the reflections in your eyes create artifacts, so it's best to keep them closed during the scan. We got some useful scans but they still had artifacts. I chose Rhino to fix them.

It was quite hard because I've never handled meshes, but I managed with the help of my friend YouTube.

The most useful tools were Mesh / Repair Tools / Repair hole and plain old selecting and deleting. Mesh / Bridge was also useful.

A simplified mesh with 10k triangles in Rhino format can be found here.

XXIst century Venetian mask

I wanted to use my scan to build a Venetian mask by flowing some abstract pattern on it. My plan was the following:

Option A: 1. Produce an interesting pattern of solids on a flat surface. 2. Flow that along the scanned face.

Option B: 1. Generate a grid on the face 2. Create an interesting pattern of solids using the PanelingTools plugin.

Common path: 3. BooleanUnion the solids. 4. Offset 1-2mm the face, BooleanDifference the union minus the offset face.

Most of my problems were related to steps 1 and 2.

The first problems came with the size of the mesh: the original had something like 450k polygons.

After fighting my computer for a good part of an evening I reduced the mesh. I reduced it to 50k and then to 10k, which was a lot easier to work with and didn't impact quality in an obvious way.

I then proceeded to get a closed mesh. ShrinkWrap (a new function in Rhino 8) was super easy for this. It will produce a closed mesh enclosing whatever collection of solids or surfaces you give it.

That was one of many dead ends. I did get a closed mesh, which might be useful in the future for printing, but is useless for my immediate aim: Neither FlowAlongSurfacenor PanelingTools work well with meshes or SubDs, nor do they require a closed shape. Oh well. A learning experience.

Another dead end for now that might be useful when I use the scan for other aims was applying QuadRemesh on the original mesh. That produces a mesh composed only of quads which can be then transformed quickly to a SubD, which can be converted in turn to a polysurface.

The resulting polysurface is well ordered and is composed of a reduced number of individual surfaces, instead of one per face in the original mesh. That makes it a lot easier to use it as the target in a FlowAlongSurface command.

I still didn't get exactly what I was looking for, but I got somewhat close. However, the shpes after flowing were twisted and didn't work well with solid boolean operations:

In the end the simplest way, about which I had known from the start, was the winner. I used Drape to generate a polysurface that covers the face from the front and then used that as the target for flowing. I had discarded this option from the beginning because it produces a uv grid that is not evenly distributed, but that is not as important for flowing as it is for paneling.

It was important as well to use the rigid option when flowing, or the boolean operations after that would not work well on the twisted solids. I flowed the shapes then spent 10 minutes or so hand tuning the final positions and distribution, as well as eliminating the smallest ones.

3D printing

3D printing the mask was quite easy compared to the design. It wouldn't have been possible to make with traditional fabrication methods because of the complicated shapes and the over and undercuts. It would be impossible to make a mold to cast it, for example.

For slicing I made sure that the smallest shapes in the mask were big enough for the printer and set it so that the inner side would connect to the support, so that the outside would be as clean as possible. The settings were the defaults for Cura with a .6mm nozzle: .2mm layer height, 200ºC nozzle temperature, 50ºC bed temperature.

I used the Ender 3 pro that has a 0.6mm nozzle installed but it still took around 24 hours of printing and 200g of material, of which I estimate around half goes to the supports. I set it before leaving for the weekend and by Monday it was done.

The end result was not perfect, but it made the impression that I was looking for, something between technological and organic. Someone on the global called it "not apt for trypophobiacs"!

And it did fit me perfectly! For future reference, the offest that I used was 2mm out from the surface of the scan.

If you want, you can download the face mask STL from here.

TODOs / Unpursued ideas:

TODO: make a mould for a silicone stamp with my logo, to use as an ex libris.

Idea: write a parametric script that builds the STL bricks for a shape (como la cubierta catenaria impresa que he visto por aquí).

Idea: write a parametric script that takes a paneling solution for a surface and outputs the plastic joints to keep it in place while welding the steel girders.

Idea: Scan object and create an origami kit from it by unrolling a simplified mesh.

• Ivy basic mesh unroll
• Tetra for grasshopper.
• F8LD Mask - unfolding animationNOT.
• Unfold Mesh. MeshToNurb.

Idea: scanning a face and making a printable mask from it. Done! * Mesh to Surface. * ADVANCED RHINO / DRAPE / FLOW ALONG SRF