For my latest CAD assignment, I have to model a pair of existing sunglasses. I started by gathering the data from the physical glasses; disassembling them and measuring and photographing all of the parts.
There are a bunch of small screws that hold the glasses together. I’m sick to death of modelling threads and since the purpose of this assignment is to produce good curves using surface modelling, I spent the least possible time modelling the screws.
I used the built-in toolbox which has a vast library of pre-existing fasteners from an array of international standards. The specific screws I wanted to use didn’t exist in any of them, so I added my specs to the database to produce what I was after.
After completing all my solid parts, I started to learn surfacing. Projecting curved lines in 3D space from two 2D sketches is a revelation. After tracing the image and projecting curves, creating the surfaces was relatively straight forward. It’s a series of lofted surfaces that are then stitched together and turned into a solid.
Using “curvature continuous” fillets instead of “tangent” fillets creates a much smoother overall surface.
Using online video lectures rather than in-person ones has been challenging. While my lecturer insisted that the hinge sat back from the edge of the arm, it was clear that mine sat proud of it. I had to reconcile with the fact that all of the glasses are slightly different after manufacture and that as long as my measurements were accurate to my glasses, hopefully I wouldn’t get marked down.
Eventually I realised that the glasses from last year that were used in the video actually were quite different to the new batch that we’re all using. My concern was totally unnecessary.
To create the frame of the glasses, I created a curved boundary surface, then cut out the front profile. I offset this to the back of the frames and then lofted between them.
The offset surface came out differently than I’d imagined, so I had to keep going back and altering the start and end of my original boundary so the surfaces showed smooth even when offset.
I chose to do a straight loft because there is only the slightest fillet on the edge of the frames.
When it was time to finish the frames by creating the nose bridge, there was no video for instruction. It was easy to do however, because I’d done something similar when modelling my iron. I traced the top profile, extruded it into a surface, then cut out the front profile and thickened it. I then projected a cut onto the surface to create the embellishment. This process probably would’ve been just as easy working with solids as it’s such a simple shape.
Once again, there was no video on how to do the upper rim. Following the same steps as I did for the frame, I came up with a result that I was very happy with.
Of course, when I wanted to mate the rim with the frames, they were completely opposite shapes! I edited both until they fit together better. I wasn’t as happy with the curves of each part, but at least they matched.
I used the in-context assembly online tutorials to cut cavities into the part, which worked really well. And naturally, two hours into those videos I found a retrospective tute on how to make the rim in the first place. It was a much simpler process of just off-setting the surfaces from the frames to make the rim and converting the lines to cut the shape.
Fun fact – if mirroring doesn’t work. there’s an option to “create opposite-hand version”
I’m pretty happy with how my glasses have turned out, but there’s still a lot of work to do. I need to render images and an animation, produce a technical drawing and model a human head.
I also have to come up with a custom design to enter into a glasses design competition and for use in the next phase in our assignment.
I took my inspiration from the unabomber, grumpy cat, and my general disdain for having to do more work. I also want thick arms because I hate it when I’m wearing sunnies and the sun comes in anyway from the sides.
Fortunately, the design I’d been thinking of and hoping would work looked like it might. I practiced my rendering, trying to get the reflections on the glass right before I submitted the final design.
It’s definitely not the worst thing I’ve ever drawn.