CAD modeling A/V Editing

Week Overview
This week focuses on computer-aided design, rendering and audio/video editing. There isn't a clear application of a development plan since this week has several focuses and learning outcomes. However, in terms of modelling the final product, I will initially model a few integral parts and continue with other parts depending on time constraints.Having gained some fluency over the past year with Fusion 360, completing an online-course and a number of tutorials. I decided to expand my skillset and learn two other programs to overcome some of Fusion 360's limitations and extend my capabilities in CAD and rendering. I chose to learn Solidworks as it's used by over 2 million engineers worldwide and is an industry standard, able to produce powerful mechanical simulations. I also wanted to choose a rendering program. Initially I was drawn to Keyshot, but after realizing that I won't be able to use it afterwards due to its hefty price tag, I continued looking. I eventually found Simlab, which uses the same rendering engine as Keyshot and even has some extra perks. Firstly it has a much lower pricetag and the availability of a lite version, Simlab also contains both a Fusion 360 and Solidworks plugin. This would allow me to have my models automatically updated if the design in Fusion is altered.

Video Editing
The CAD documentation in this week and throughout the course of the final project will be primarily documented by screen recordings. It saves space on the page itself and allows a quick runthrough of the complete modeling process. If one desires to, the youtube player also allows speed control to slow it down, making it easier to follow along. In this week I designed a few components of my final project as well as a mini-project. All screen recordings were done on Quicktime as it's the native application for screen recording on Macs. To screen record simply have the window in full screen, open Quicktime, click on file==> New screen recording, then click on the record button to start the recording. Once the recordings were complete, I used IMovie to edit and trim the clips, increase the playback speed as well as adding a title and accompanying music.

2D Illustrations and Image editing
For 2-dimensional non-parametric design, I decided to use Adobe Illustrator. I have some prior experience using this software, mostly for simple graphics like the ones included in my website. However, I decided on taking a more artistic challenge, to design a sticker for my laptop, which I can print using the vinyl cutter/printer in the upcoming week.

I started with a few reference photos of a worm in an apple cartoon, a picture of my laptop cover and a particular caterpillar whose peculiar shape I'm fond of, the cecropia moth caterpillar. The photos needed some editing before being able to use them to create my design, so I took the opportunity to learn a few simple tricks on Adobe Photoshop. I read the following tutorial on removing background color to remove the background and any unwanted parts of a photo. You can see below the original and resulting photographs. Below are the buttons required to reach the menu shown on the left with the parameters for tracing the photo and vectorizing it.
I then imported the edited photos into illustrator and screen recorded the process of designing the sticker artwork. The method of converting the caterpillar's image to vector graphics was the image trace command, with options to control the color range and detail level. As can be seen, I tried different approaches and workflows since I wasn't sure as to which would render the best result.

Parametric 2D-CAD on Draftsight
For parametric 2-dimensional CAD drawings, I picked Dassault Systemes' Draftsight. Since 2D is simpler and easier for someone who is familier with 3D modelling, I went through a written guid on Drafsight by CADOasis . After reading through the tutorial and familiarizing myself with Draftsight's features, I took upon creating a design for the Cajon drum I wanted to laser-cut in week 3.

Back View

Back View

3D CAD on Fusion360
I've started designing the wheels since they probably wont change throughout the development of the project. The wheels are modeled for all terrains and are supposed to make going up and down a step easier. The inspiration for this design and detailed sketches/dimension can be found . I modeled a first prototype which involved geometric and parametric designs, extrutions of profiles, revolves and circular patterns. After running a simple simulation, it seemed like much of the stress is focused on the axel. This was probably because the cuts in the wheel body were denser around the axis than near the wheel's circumfurence.

After performing the simulation, I flipped the polygon pattern to decrease in size as it gets closer to the axel. This allowed me to produce a much lighter model with better force dissipation and less stress concentrated at the axel. I performed a simulation with double the force and the result was closer to what I was aiming for.

For the back wheels I used the same concept but with less flexion since the patient will be applying more load to the back of the walker and I want to ensure better stability. It was acheived similarly to the front wheel using extrusions of the wheel's profiles, circular patterns to repeat extrusion patterns and fillets to curve the corners. Revolute was used to crate wheel traction patterns.
Front wheel model
Back wheel model

Learning Maya

Initially, I did a few tutorials on Maya since it was my first time using the program. I started with modeling a tennis ball. I then used the resulting model in the next section while testing out Simlab lite's rendering environment and features.

I then took up a more complex character modelling tutorial. I must admit it was quite a challenge especially when the mesh manipulation is done with a very different workflow than T-spline modelling in fusion. The program crashed halfway through which turned out to be a good chance for me to attempt modelling the same character without following the tutorial walkthrough. This might come in handy when creating rendered image of the final project; adding moving human models using the device and animating them.

Rendering in Simlab
Simlab Lite's interface seemed quite straightforward after downloading it and I decided to explore it by myself and experiment with different features. I was already familiar with some rendering concepts from fusion so I took a go at rendering the tennis ball modelled earlier in Maya.
The rendered image

After watching this video on animation and simulation in Simlab, I decided to try and make the tennis ball bounce. I had now activated the full version of Simlab since this feature isn't available on the lite version. It turns out that Simlab outputs the animation frame by frame, so I imported the images into Imovie and had them presented in sequence at a fast speed.

Please find all the files required, if you feel like taking a look:
File Link
Caterpillar Image
Tennisball model