Danny Griffin HTMAA 2023

Week 03 :: 3D Scanning and Printing

How do we move points back and forth from digital to physical space?

1. 3D Scan an Object:

To start prototyping wearable devices for my final project, I wanted to use this week to put together a 3D model of an arm.

Responsive image — For scanning, I used a video from my phone to collect footage in a circle around the arm. The arm in question belongs to Inez Ow, who will eventually be helping to test my wearable device.

For processing the images, I used the software Agisoft Metashape.

The process begins with importing jpeg images, frames from the video, and using the softare to align the camera positions.

From the cameras, you generate point clouds, which you can filter by confidence. This image shows the result I was getting once I filtered out the low confidence points.

Tie points layer showing rough alignment of the initial point cloud.

3D model layer, showing the mesh interpolated through the point cloud.

The first thing I did to process the mesh was to scale appropriately using measured dimensions from Inez's arm. At the outset, I also set up some reference planes to start to discretize the geometry, since the overall dimension of her arm would not fit in any of the printer beds I would be using.

During the manual refinement process, I looked at the texture map to see areas where there should be spaces between the fingers, deleted points in the mesh, and used the MeshPatch command to rebuild at higher fidelity. Correcting for the "webbed fingers" of the Metashape mesh is not as high fidelity as the original scan, but I think for the purposes of wearable design, it's more important that I have clearance in these tight areas than 100% accurate mesh geometry.

2. Group Assignment: Test the Design Rules for your 3D printer

Modeling 0.75" wide x 0.1" deep x 2" tall extrusions, we angled them in 6 degree increments from a perfectly straight wall to a nearly horizontal cantilever.

3. Design and 3D print an object

Testing.

I chose to first print with the Sindohs as it would be the quickest way to verify dimensions of my scan, and guage whether I built my meshes correctly.

For all settings including raft and infill, I used defaults in the 3Dwox software.

Removal process of the rafts and support structure. Minor sanding was needed to get the parts to fit together.

During the course of this process, I started to have many new ideas about construction of my wearable. I see now that I could use the 3D print of the 3D scanned arm as a positive to create casting moulds, or to 3D print flexible material onto the arm. I will explore these directions once I'm confident that the 3D print is the right dimension to proceed.

4. Formlabs Testing

This week, I wanted to test one alternate direction, which would be to use a Formlabs printer to print flexible material for the housing of my final project.

To this end, I quickly dove into self-teaching and troubleshooting on the Form 2 machines at the Self Assembly Lab.

I initially tested prints in two materials - clear resin and flexible resin. Due to my inexperience troubleshooting, all of my prints failed to different degrees.

Though my prints failed, I took the fragments to the cure chamber just to see how the print properties turn out.

Surprisingly, the resin prints were compatible with the Sindoh prints with no processing necessary.

For the purposes of the project I'll be doing in this class, I'm not sure that I need the quality of the resin print.

However, I'm pleased to discover that the process of submitting jobs is so similar to the process of preparing a Sindoh print.