02 | Computer-Aided Design

Lecture

Review

Weekly assignments

Computer-Aided Design

1. Model (raster, vector, 2D, 3D, render, animate, simulate, …) a possible final project, compress your images and videos, and post it on your class page.

Have you?

• Modelled experimental objects/part of a possible project in 2D and 3D software.
• Shown how you did it with words/images/screenshots.
• Included your original design files.

Magic Lantern

I have used this week to test out a real magic lantern from the 1800s and to understand how I should build one from scratch. The lantern that I have is not complete and some parts don’t actually fit together.

I managed to get it working though with an LED flashlight and some ad-hoc support pieces for the lens.

Fusion 360

For 3D software, I used Fusion 360 to create the models. This week is really heavy with other tasks for me at the university, so I decided to not try to learn something new, but rather just focus on designing a preliminary version of my final project. These files will not be the final design files as I have not considered how to fabricate the parts or even decided on the materials. My goal was to figure out the overall scale of the device and to have something that helps me understand what would be the best way to build it.

Firstly, I made a rough version of a chromatrope slide based on a real one. And then I made a rough version of the lantern. This capture shows me playing back the timeline of my process:

I wanted to also start working on a functioning replicate of the chromatope I have. Therefore, I modelled a holder for the slides that can be rotated by manually cranking them. Here is the final result.

Generating gears in Fusion 360

I need to replicate the gear mechanism of a real magic lantern slide to make my version of it. I took apart one of my slides to see how they work. This is what you can find inside.

The slide has bevel gears attached to the slides and one pinion gear drives both of the slides. For the video below, I removed the other slide.

Gear ratio:

• Pinion: 10 teeth
• Wheel: 144 teeth (if I counted correctly)

Built-in spur gear tool

Fusion has a built-in gear generator script, but it only does spur gears. That is very helpful to know but doesn’t really get me any further with my process.

GF Gear Generator

GF Gear Generator is a really good (and free) plugin that allows you to easily create different types of gears. It is able to do bevel gears, but not really in the size and shape that I’m after.

Download

FM Gears (Windows only)

This seems really nice too, but my Windows computer is not working at the moment so I couldn’t test it.

Download

Labbers Spur Gears by Niklas Pöllönen (Mac and Windows)

Another free tool for spur gears. Niklas is a New Media alumni from Aalto University and used to work at the Aalto Fab Lab.

Download

Rack Gear Generator by Niklas Pöllönen (Mac and Windows)

This one can be used for making rack gears. Another one made by Niklas.

Download

Bevel Gears?

Sadly, only the GF Gear Generator supported bevel gears, and with that one, I could not generate the gears with the size I wanted.

There are some paid plug-ins though:

• Bevel Gear Maker (Basic) - $20
• Bevel Gear Maker (Advanced - $40)

Bevel gears the manual way

I found some tutorials for making bevel gears manually.

What did I end up doing?

Firstly, I had some issues getting any plugins installed, so I attempted to make the gears manually. It started getting very complicated with the size and gear ratio I need to use so I decided to try to find a way to install the plugins. After some testing, I found out the following.

I have a new M1 Mac and at least for me, most of the plugins do not successfully install. I found out that this is the issue. Follow the instructions to get them working.

Seems to be an issue with how overprotective the macOS is, they installed fine on my older intel-based Mac with the same operating system, so maybe Apple sets some more strict settings with the new processors. Anyway, I was able to manually move the files to the correct folder.

The fix:

• Download Suspicious Package tool
• Open the installer file for the plugin
• Go to the All Files tab
• Find the folder that ends with .bundle
• Right-click and Export the .bundle folder
• Copy the exported file to these folders:
  • ~/Library/Application Support/Autodesk/ApplicationPlugins
  • ~/Library/Containers/com.autodesk.mas.fusion360/Data/Library/Application Support/Autodesk/ApplicationPlugins

So after trying the manual way and spending way too much time on that, I decided that my time is worth much more to me than the $40, so I gave-in to buying that plugin for bevel gears. Great decision because it actually helps me to quickly understand all the different things I need to consider.

Here are my settings for the Bevel Gear Generator

p5js

For the 2D side, I started with a slightly unorthodox way of working. For the first slide that I will make, I need to create geometric, decorative patterns that will be printed or etched on the slides. As I work a lot with creating generative graphics with code, the natural way for me to start designing these types of patterns is with something like p5.js, which is a creative coding library for JavaScript based on Processing.

Unfortunately, I did not have time to create a system for generating the patterns—I will tackle that during the computer-controlled cutting week—but I was able to create a testing tool for understanding what kind of patterns would be suitable as chromatrope slides.

This is a demonstration of this tool using scanned slides from original chromatropes. Lucerna Magic Lantern Web Resource, lucerna.exeter.ac.uk, item 3009241. Accessed 9 February 2022.

Run the sketch and move your mouse around so that the slides align.

Cuttle

I also wanted to explore Cuttle to create some of the geometric patterns for the slides. Cuttle is “a design tool for digital cutting machines” that allows you to do parametric designs and edit them using modifiers or scripting. One of the developers is a friend of mine and he works from my studio space here in Helsinki. I really want to properly test this tool so I will most likely try to get some one-on-one tutorials from him in the coming weeks.

Cuttle is an web-bsed tool that runs on the browser. There are some basic shapes and drawing tools you can use as the starting point and then you can add modifiers to create more complex shapes. I will build something like this in p5js but for now Cuttle is a great tool for visually exploring different generative shapes.

Below is a video where I do the following:

1. I draw a Logarithmic Spiral
2. I scale and position it so that the start of the path is in the origin
3. I add a Rotational Repeat modifier
4. I change the line width from hairline to something thicker
5. I start dragging the points of the path until I get something I like

Design files

• Chromatrope Slide & Magic Lantern (Fusion 360 archive of both files)
• png images of the slides: A and B

I couldn’t upload the model of the slide with the gears because for some reason, Fusion made the file size almost 100MB. Haven’t really figured out yet what is causing that.

Here are interactive viewers of the models: