Week 2 Assignments - Computer Aided Design

2D Design Tools

This week considered 2D design tools for both raster (pixel based) and vector (geometry / formula based) design.

Raster Design Tools

The primary 2D raster design tools I have installed and explored are ImageMagick and GIMP. I also include FFmpeg here as a tool for video management.

ImageMagick

ImageMagick is a command line tool that has primarily been used for managing image file format / size. With some experimentation, I settled on the following options so far:

• -verbose - shows details as the command runs
• -strip - removes profile and metadata information
• -resize - gives a target size - the example specifies the height dimension, and the width scales accordingly
• -quality - suggests a target level of quality to maintain in compressing the image
• -format - image file format for output (jpg allowing for compression)
• -path - destination for output files. I have organized image files into weeks. For each week, there is an image folder for the images being used. Original images from screenshots etc. are placed in a sub-folder original, in case I need to go back and re-do some image processing. This presumes the command is run in the original folder and puts the output into the image folder (one up) for use.
• .png - most image files so far start as .png, so .png processes all .png files in the folder

magick mogrify -verbose -strip -resize x400 -quality 75% -format jpg -path ./../ *.png

FFmpeg

FFmpeg is a command line tool that has primarily been used for managing video file format / size. With some experimentation, I settled on the following options so far:

• -i - input file name
• -vf - video filter options
  • scale=width:height in pixels, -1 to autoscale one dimension with other
• -c:v - for the video stream, use libx264 (H.264 codec) for encoding
• -crf - set Constant Rate Factor for balancing size and quality
• -preset - set encoding speed and compression efficiency tradeoff
• -c:a - for the audio stream, use aac (AAC codec) for audio
• -b:a - for the audio stream, use bitrate of 128 kbps

ffmpeg -i wk2-fusion-gear-animation.mp4 -vf scale=500:-1 -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k output.mp4

GIMP

GIMP so far has primarily been used for more visual image processing. This includes:

• Visual cropping of original image content Tools > Transform Tools > Crop
• Flatting transparent (alpha-channel) borders Image > Flatten Image and removing borders from screenshot images Image > Crop to Content.

Toward modeling final project content, I also explored some image effects that could be used to create a vintage, weathered look for a printed background on the clock face. Face lines / text were created in Inkscape (see below), and the weathered background was created with GIMP.

Vector Design Tools

The primary 2D vector design tools I have installed and explored are Inkscape and Cuttle.

Inkscape

I have some limited experience with 2D vector tools for drawing, such as Inkscape and Adobe Illustrator. I decided to focus on Inkscape as a more broadly available tool. As a brief refresher, I went through the Inkscape official tutorials for:

• Basic Tutorial
• Shapes Tutorial
• Advanced Tutorial

Toward modeling final project content, I used Inkscape to create a prototype clock face design. This involved creating a template design for the scrollwork, and the pattern along path feature to repeat the design around the clock face.

Cuttle

From the week 2 discussion, I had found some favorable references to Cuttle, and I decided to try it out. I made a brief exploration of the video tutorials, and worked through the following introductory tutorials:

• Getting Started with Cuttle - Part 1
• Getting Started with Cuttle - Part 2

I found Cuttle to be a very intuitive and easy to use tool for 2D vector design, and I expect that I will explore it further as a potential primary tool for project 2D vector design. It seems to me that there is a noticeable UX difference between tools more generally designed for drawing but are used for cutting design (e.g., Adobe Illustrator, Inkscape) and Cuttle, which is more specifically developed for cutting design.

Toward modeling final project content, I re-created the prototype clock face design that I had done previously in Inkscape. There were a lot of similar steps, but the Cuttle process felt a little smoother.

3D Design Tools

This week also considered 3D design tools for modeling and simulation of three-dimensional bodies, components, and assemblies in design. I explored Autodesk Fusion and Onshape.

Autodesk Fusion

I have some limited experience with Fusion, but certainly needed a refresher. I have found that many of the learning materials and tutorials out there are either targeted at a different audience than myself or they are simply not so helpful.

A tutorial series that resonated with where I am at is one from Product Design Online. They have a video series to Learn Autodesk Fusion 360 in 30 Days for Complete Beginners! Some highlights are:

• Day 1: Step by Step (Toy Block)
• Day 5: Pattern This
• Day 17: All 12 Fusion Sketch Constraints

Toy Block Tutorial

I worked through a number of tutorials to review fundamentals in fusion. I document the process for the Toy Block tutorial specifically. This is both to illustrate the tutorial review process in Fusion and because this basic design process is what I used for a point of comparison with Onshape.

Initial 2D sketch for toy block body

Extrude toy block body

Sketch for initial top connector

Extrude initial top connector

Rectangular pattern for connectors (screenshot process omits pattern detail)

Rectangular pattern for connectors (pattern detail)

Shelling toy block interior

Sketch for interior connector (circle and offset)

Extrude interior connector

Rectangular pattern for interior connectors

Fillet top connector edges and top block edges

Final toy block design

Gear Modeling Toward Final project

Toward final project development, I explored gear design in Fusion. The clock mechanism will likely involve independent motors using gears to drive different shafts in order to actuate each of the clock hands.

I worked through a tutorial in Fusion on how to Create Custom 3D Printable Gears in Fusion 360. This involved

• Installing the gear creation plug-in tool
• Working through option settings for gear parameters
• Center holes for gears
• Hollowing gear body to reduce material / friction
• Creating a mount for 2 gears
• Creating gear joints for articulation
• Creating a motion link to connect 2 gears in articulation
• Creating a motion study to explore motion actions
• Using the McMaster-Carr connected library to import gear designs

I explored the rendering tools in Fusion to

• Apply material textures to the gears (green and blue plastic) and base (black plastic), as well as to the gear from McMaster-Carr (metal).
• Add an environment / lighting to the screenshot
• Render the image

I also explored the animation tools in Fusion to

• Explode the parts for individual viewing
• Animate the parts to show how they fit together

The following video shows the animation for the gear assembly

The following video shows the motion study interface, as well as the motiion link with direct interaction.

Onshape

As a point of comparison with Fusion, I explored Onshape, which I have not used previously. I tried going through some of the official learning matrials from Onshape, as well as the learning pathway within the environment itself. These were not very helpful to me in trying to get started. They seem to be a good introduction or reminder for someone who is trasitioning with more extensive experience from another CAD tool, or as a reminder for someone who already knows Onshape. I did not discover a separate tutorial series that was a good fit for me.

So, I decided to try and work through the steps for the toy block development from Fusion, but figuring out how to do things in Onshape. I did try to find a similar toy block tutorial for Onshape. There were some, but they tended to be more confusing than helpful. In the end, I worked through steps of the previous Fusion tutorial, but searching out how to do those operations in Onshape.

I like the browser-based environment and the online-document type feel, but I found some of the navigation and operations to be more tricky than in Fusion. It seemed to be easier to mis-click in the interface and get off track, with more time spent trying to rectify. There is probably a way to do it, but a particular difference is that it seems more important to do patterning (rectangular patterning) within sketches in Onshape, whereas it is more straightforward to patten features in Fusion.

I followed the same basic steps as in the Fusion tutorial, with the following result

Project Design Files

For the activities toward the final project, following are the main design files.

• Inkscape clock face (svg)
• Cuttle clock face (svg)
• GIMP enhanced clock face (xcf)
• Fusion gears (f3d)