Computer-Aided Design

Summary

This week was fun. Building things in 3D, and letting your imagination run wild. The only thing stopping it was the lack of experience with the tools. The model turned out pretty successfully considering. However, this first fumbled attempt as visualising my proposed project has highlighted a few issues in the design, and a few constraints that it will be bound by. Not bad for a first attempt.

What I thought I knew before

My experience of 2D design in vector and raster graphics is long. Using Adobe Illustrator and Photoshop extensively for work. My 3D experience is limited, although i understand most of the theory.

I prepared a little before the start of the Fab Academy by looking at a few open source (and commercial software packages (capable of parametric design), and settled on Fusion360. It seemed very user friendly, and boasted features like animation and PCB designing possibilities. I followed some tutorials on a well known video streaming site and gave myself a good basic grounding of the software and terminology used in engineering design.

Learning Outcomes

Theory and use of things i learnt from this assignment:

Creating models in 3D, which are “parametric” in dimensions and can be realistic in measurements.

Lessons to take away:

Choose your tools quickly. With so little time to finish the assignment each week, its imperative to get going with work quickly. So assess all the tools and pick those that will work best for you.

Learn the features of the tool quickly. Once you get a feel for what the tool can do, you should have an idea on the workflow you’ll use to do your work.

Don’t spend too much time watching/doing tutorials. This eats into the amount of time you have to work on your assignment. Watch the tutorials that are relevant to the workflow that you have already discovered, at the time you need it. ‘Just in time delivery’,

What I did

After seeing all the tools being demonstrated, i still preferred using Fusion360.

Fusion360

• Modelling

I decided to try out making a few “practice models” to get into the swing of things, before i tackle the main model. I decided on a simple LED and a possible 3 axis sensor. I searched on the internet for data sheets on these components to find real-life measurements and therefore get a realistic view of my model. I could’ve imported these from a library into my main model, but thought that was cheating at this point in my learning of computer aided design.

I modelled the LED, applying realistic materials to the materials. To try and get a glowing LED, i hoped that Fusion360 would include some particle (light) emitting function like Blender. It did include an emitting LED emitting material especially for this model. However it wasn’t opaque, and my modelling of the anode/cathode was lost. So I improvised and created a small body in between the anode/cathode and gave that the emitting material - just like in real life.

Using functions such as “pattern”, “mirror” I arranged multiples of these components on a disc which would be the PCB board in my model. This would be just to give the impression of having electronics on it, and give some sort of scale to my main design.

• Parameters

For the main model I tried to base the measurements on relationships between the parameters. Trying to reduce the amount of parameters needed to be changed should there be issues in the design. Much like a coding. I made favourites of the parameters i would possibly need to change in the future.

• 2D Sketch

Drawing the 2D shapes and spline was pretty easy once the parameters had been set. Setting their dimensions to the parameter (variable) names quickly and adding constraints between the lines and splines meant that i would only need to change the values in the parameters box if i needed to change all the shapes.

Looking at the values these algorithms gave the dimensions in the drawing, i thought it would be much easier to create the model in real life if they were nice integer numbers. So I added maths functions to some of the parameters to bring the numbers to the nearest mm.

• 3D modelling / sculpting?

I was torn on the way to model the main device section. The two sides of the “straps” wre extruded easily from the sketch and and chamfered the edges. This was mirrored to make 2 sides, from which i would make the different amendments needed on each side. Holes on one side, and fastening “stalks” on the other to fit through those holes. Again, all the dimensions of the extruding and modifying functions related to parameters.

The middle section to house the electronics could be made in several different routes. I decided to stay with the “Extruding” method from the sketch (in 3 axis), and leave a shape where they all intersect.

Adding an offset of the thickness of the material i would be hypothetically using, gave it some “body” and a cavity to which i could import the PCB board with components into. Obviously, to get this into the cavity in real life i would need to make a hole, so i cut one out with a small “lip” , to hold the PCB board in. The hole would also allow the back of the electronics to be exposed with sensors able to measure parameters on the skin.

When trying to smoothly loft the two straps to the cavity, things started to go wrong slightly. The extrude method to create the original “half” elliptic sphere shape didn’t leave man points on which to attach the faces of the straps. Thus minimising the ability to chamfer the edges and create a smooth connection. It would also leave places where the concentration of force may cause the “product” to break.

• Analysis of the model

On analysing the section of the model to see what was happening inside of the cavity with the PCB board i found some issues (see below). I also realised that this would make a cool stop-animation shot for the animated film of the model. So I capture the image of the analysis each time it moved a small step through the models.

Adobe Premiere

• Edit
• Colour grade
• Finishing

Importing all the image sequences into separate timelines were easy due to the way saves the screen grabs and image captures. Then it was a case of adding the different sequences into a master timeline, where i added transitions, slowed down the “stop motion” sequences, and threw on a few Sci-fi/futuristic sound effects for atmospheric purposes. It was made pretty easy and quick due to most of the editing being done in the design of the animation shots in Fusion360 . A few other touches and a basic film was completed.

Adobe Media Encoder

• Export

Exporting the film was bit of a problem. In my professional life, using the highest quality settings for encoding is paramount to ensure the quality of the image. Here i had real trouble getting the 43 seconds down toa file size less than 10Mb. This is the packet limit of the Gitlab repo. Reducing the Full HD resolution of the project file to 720p HD, bitrates to a target of 1,5 Mbps with a Max 2 Mbps. Some banding artifacts were seen in some of the transitions, so note to self be careful which ones to use next time.

What I should’ve done

Used a vector graphics programme for something. I don’t know what i could’ve used it for in this workflow as Fusion360 had enough tools and features for me to create the overall assignment.

Mistakes & Issues

Different ways of modelling the cover above the electronics board. I struggled a bit to think of a route to make the shape of the cover of the electronics board. I sketched out the dimensions (Ellipses) in 2D in 3 axis and proceeded to extrude along them. Cutting one axis extrude from each other. Although this made a smooth shape, the programme gave the shape unusual vertex points to express the connecting polygons. So parts of the drawing of the shape look a little strange and it was difficult to attach other bodies to them. I’ll need to find another technique to create the flowing organic look that i’m hoping for.

Analysis of the model. Using some of the tools to analyse the structure of my model, i found that i need to take care with the separation of the cover above teh electronics board. I’ve used a traditional LED, the height which could potentially be a factor in the overall height of the device.

Animations in Fusion360. While its pretty easy to make simple animations using Fusion360, i wish i had time to learn Blender and be able to get exactly the shots that i could see in my mind. It does have an interesting “exploding” design function i wanted to use, however the modelling file and the way i created it limited the correct working of this. Next time i’ll have to make a special file just for this shot that only contains a list of components.

Not using a Vector graphics programme during the assignment. I didn’t need to use a vector programme to create my model, although procedures and techniques shared with vector graphics were used in making the “sketches” in Fusion360. As a way to show that i am capable of using Adobe Illustrator to create vector graphics in varying file formats i’ve included this .svg of the Waag Logo.

I’ll probably use it on the vinyl cutter next week ;)

CONCLUSION

I’m definitely heading in the right direction with my design, some work will need to be done to the design to fix the issues discovered from doing this assignment. It’s also easy to lose track of time when creating 3D models.

FILES