3. Computer-Aided Design
Goals for the week:
2D Modelling
For two-dimensional modelling, I chose Adobe Illustrator. This is but one of many options, however it was what I was most comfortable with, and since Wheaton College gives me free access for attending Fab Academy, it's the one I would work with and explain. I have used and can recommend Inkscape and GIMP if you want a free option.
This image displays the difference between a vector-based image--which is created using points connected using paths,
and a raster image--which uses pixels of varying color/hue and brightness to create what is called a "bitmap" of the final image.
As you can see, when zooming in on a vector image, there is no compromise of image quality, as the image is made of shapes filled in with solid colors; for the raster image, once a certain zoom level (or image scaling) is reached, image quality can decline quickly, showing the edges of the pixels.
These are the shape tools you have access to in Illustrator. The one I use the most is the rectangle tool, primarily to create what is known as a 'clipping mask', which effectively just a fancy image crop tool. To see the other shape options, you can right-click on the rectangle tool icon. Later on, I used the line segment tool to create clipping masks with more complex shapes for the making of my project poster.
Software Limitations & How I Made It Work
Adobe Illustrator is first and foremost a vector-based editing software; for raster editing, it is far better to use Photoshop or Inkscape. However, there is a handy 'rasterize' tool in Illustrator if you need to convert a vector image into a raster, which is useful for keeping your file sizes down. Another way you can turn any vector images you create in Illustrator into their rasterized counterparts is by right-clicking the image, and exporting the asset as a raster-based filetype (.png, .pdf, .jpg, .gif, etc.).
To create the wonderfully crafted image seen above, I first imported an image of the Fab Academy Logo from Google Images into Illustrator, created a copy, and rasterized the copy. Then, I zoomed in on a section of the logo, used the rectangle tool to create a clipping mask of the area I wanted, and copy-pasted the result next to the original image. I repeated that procedure once more to get a better look at the difference between the images, and used the 'add text' tool to label them for viewing purposes.
3D Modelling
Fusion 360
I chose Fusion 360 for Personal Use as my CAD software as it seemed like it was simple enough to use and had a free version available for download. Other options that I know some fellow students chose to use are FreeCAD and Blender, though Blender seemed to be more for 3D rendering/animation rather than manufacturing purposes. Regardless, once I had downloaded the program and created my Autodesk account, I was ready to start my first project.
I didn't really follow any tutorials myself at this point in time, but I later found a wonderful resource on the Autodesk support forum that I referenced once or twice when I got stuck or confused. I will link it here as well as in the links section.
I still hadn't decided on a final project at this point, so I wanted to try and make an idea of what a pet tank fogger could look like. The first step for that was to set my parameters. These are like dimensions of your model, and this window allows you to make changes to your design without having to go through and re-make parts to fit those changes. If a model is properly defined parametrically, you can change any of these values and your model will adjust any related parts to accomodate those changes.
I decided to make a scale model of a 20 gallon long tank to see what I was working with and to get used to the tools at my disposal. To make any bodies, you first need a sketch profile to work from, so I selected the bottom plane and sketched out the bottom panel of the tank as well as the wall thickness.
To turn my 2D sketch into a 3D body, I used the 'extrude' tool on the profile of the tank walls and set it to the TankHeight parameter; and extruded the profile of the bottom panel to the TankThickness parameter. It would've been simpler to extrude the whole profile to the height parameter, and then use the 'shell' tool to hollow out the resulting block to create walls with the thickness parameter, but I wasn't quite there yet at this time.
Then, I made a small tank that would be the fogger reservoir, branching out and using the 'loft' and 'shell' tools to do so. I wasn't too committed to the idea of this being my project, so I didn't care if it didn't look too refined; this model was more about getting used to the software and the tools within.
I thought the lid would have some interesting geometry to it since I was imagining it would have a hose connection, filling funnel with a plug, and a slot for the electrical bits to poke through and sit snugly in. With this construction, I got more used to using the 'chamfer', 'fillet', 'offset face' and 'thread' tools.
At this point, I felt satisfied with what I had created in terms of completion for this week, but I knew I needed to hone my CAD skills a lot more if I was going to use this program as much as I anticipated I would for the creation of my final project.
Unbeknownst to me, I was all too correct in that assumption, and I would get plenty of practice in the weeks to come.