This week, we covered the basics of CAD software. We looked at some alternatives like FreeCAD or SolveSpace.
For the program that I was going to use first, I chose Autodesk Fusion 360. This is a program I have quite a bit of experience in, therefore I am the most comfortable with it.
Before starting the modeling on Fusion, I ideated on possible alternatives.
I did some reflection my final project topic, which you can find in the “final project page”.
I decided to go with the “feed me trashcan”. This is a trashcan that constantly bothers you asking for food. It will have wheels that will move it around, and a moving mouth. And maybe it will make sound.
Before starting modeling, I always set parameters. A parameter in modeling allows us to set certain values to certain variables. These can all be changed later on, which provides a huge advantage when we want to modify a value that we set in the beginning.
You can see here that I have created parameters for variables such as the diameter of the base plate. If I decide to make the base larger later on in the process, I can simply change this parameter and the model will adapt accordingly.
For the main body of the can, I sketched the profile on a plane. Then, I used the revolve tool to create my first solid body.
Then I added the upper parts with the revolve tool again.
After the body was complete, I moved on the other component: the rotating head. For this, I created a seperate component first. In Fusion 360, we always create components that have a single “body” in them. Every object that is seperate from each other should be a different component.
I experimented with a few arrangements on how the moving head would be modeled. Some of them did not work due to the placement of the hinge and the position of the mouthpiece relative to it, so I had to scrap them. Here are the options I worked with.
I settled on the last option, since it provided a solid hinge point and it was easy to model. Here is how the upper mouth piece moves in combination with the body:
For components such as motors or wheels, I prefer to use ready-made models. Since they provide accurate measurements, especially if I am able to find the exact model of the component that I am going to use.
Fusion works well with .STEP or .SLDPRT files, so I use Grabcad to find models.
For this model I used models for a step motor, a dc-motor and wheel assembly, and a 360 wheel.
I modeled the holes that they would be mounted on.
I added the 360 wheel as well. I made a small mounting point at the bottom for it and also closed off the top of the wheel enclosure. Here is how it looks:
After adding these, the only thing left was to do some filleting/ chamfering. This is important both from a manufacturing standpoint, because it allows for smoother production in many different manufacturing types; and from a rendering standpoint, because without fillets the CAD model does not look well when rendered.
The next program I moved onto was Solvespace. It caught my attention because of the simplicity of it’s UI, so I wanted to explore it as a lighter alternative to Fusion 360.
I started with following the tutorial on Solvespace’s website to get familiar with the basics of the software.
The workflow is basically drawing the rough shape with lines first, then adjusting it by applying constraints. In this section of the tutorial, we go through the constraints: “horizontal”, “vertical”, “parallel”, and “perpendicular”.
Another useful feature here was the “Sketch > Tangent Arc at Point”, which allows us to automatically draw a tangential arc on a single point between two straight lines.
Now it’s time for extrusion. Extrusion operation is done through “New Group > Extrusion”. In Solvespace, operations are called “groups”, and can always be edited later by going into the group menu from the Property Browser.
After extrusion, we can start drawing the other sketch for the gusset. For this, we want to create a new workplane. To do this, we first have to uncover the hidden lines in the extrusion by clicking the icon on the far right corner of the Property Browser.
We select the point we want (highlighted in red below). Then, we rotate the view to roughly look at the plane we want to sketch on, and select “New Group > Sketch in New Workplane”. This part is important, because “if no other information is provided, then SolveSpace snaps to the nearest workplane parallel to the coordinate axes” (Solvespace Tutorial). If we didn’t do this, Solvespace could have selected another coordinate axes automatically instead.
We can always return to our view of the workplane after rotation by selecting “View > Align View to Workplane” or clicking “W”.
We draw a triangle for the gusset, then constrain it using “point on point” and “point on curve”. We extrude the triangle and change it’s color.
We want the gusset to be the same thickness with the bracket. Solvespace’s solution to doing is quite simple. Just like how we constrained two 2D sketch lines to be the same length, we can do the same with 3D lines. We select the thickness line of the gusset, and then the bracket, and apply “Constrain equal length”.
Moving onto creating the mounting holes. For these, we want to create another work plane. However, we can’t use the automatic workplane creation like we used in the sketch before, since we are not sketching on any of the coordinate planes. So, we select one point and two non-parallel lines, and choose “New Group > Sketch in new workplace”.
We draw the circles for the holes and constrain them to be the same radius. Then we apply the symmetry modifier. An interesting tidbit here is that we don’t necessarily need to specify a symmetry axis. After selecting the centers of each circle, we select the symmetry constraint. Solvespace automatically selects the symmetry axis as the vertical axis of the workplane. This is quite time saving if we don’t actually need a specific symmetry axis.
We extrude the circles. Then, in order to make sure they are going the direction we want, we use a constraint again. Select the center point of the end of the extruded cylinder, then select the face of the bracket, and apply “Constrain > On plane”. Finally, we modify the extrusion operation by making it a “difference” instead of “union”.
With this, our part is complete. Here is the final working tree of the operations we did. I renamed the operations so they are easier to track. At any point in our design, we can go back and modify these, and changes will automatically apply to our final design.
For example, I realized when I finished that I actually put the holes in the wrong plane. So I went back in the group history, as you can see below, and created a new group from there. I could have also deleted/ undo the last two groups, it wouldn’t make a difference in this case. However, if I had a much longer working tree, then going back in the history like this and changing/ adding new stuff would be a much better idea than undoing everything up to that point and starting again.
I quite liked the simple workflow that Solvespace offers. Although not as advanced as something like Fusion 360, I think it’s perfect for more simpler jobs. The UI is very easy to understand and use. Compared to other free CAD software I tried, like FreeCAD, I think Solvespace sits in a very sweet spot. It is quite capable, but also employs a very clean UI and user experience. I want to get deeper into the parametric design possibilities and learn how to create more complex designs.
After learning that Aalto has a student license for Cuttle.xyz, I decided to try it out to create complex 3D shapes to be laser cut. The fact that it was parametric really caught my attention, because of my love for parametric design tools -such as Fusion 360.
I also wanted to see if Cuttle could be a useful tool for my thesis project, which is about digital fabrication education for children. After a first look, it seemed like a fun tool to create fun and interesting-looking structures to be fabricated in a short time.
First, I went through the introduction tutorial here. After going through the basics, I dived into the Cuttle Youtube channel, as well as Nadieh’s documentation.
I went through the laser cut boxes with finger joints first. The most basic one was already a life-saver for future projects. As a person who is tired of making custom finger joint boxes every time I need a small container for something, this was a great find.
After checking that out for a bit, I moved onto this two part tutorial to learn the basics. The goal was to design a dodecahedron to be cut out of paper. Cuttle already has pre-made shapes which you can drag and drop to the canvas to edit, so we start with a pentagon and a rectangle for the flaps.
One very useful feature of Cuttle is the “modifiers”. We can add modifiers to components to create different effects, which can always be parametrically edited later on. We continue with adding the “rotational repeat” modifier to the rectangle, which creates copies of the shape rotating around an origin point. The parameters for this operation, such as the location of origin, no. of repeats, rotation angle, etc. can all be modified later through the sidebar.
After that, we do a “boolean union” to join the rectangles and pentagon as a single shape. We add another pentagon and paint it red to act as a folding line.
We move on to decorating the inside of the pentagon. After experimenting with splines with the pen tool for a bit, we apply a rotational repeat modifier. Another useful feature of Cuttle comes into play here. If we want to add a circle to this rotational repeat pattern, instead of applying a seperate modifier to the circle, we can do this instead: Group the rotationally repeated splines first, then drag the circle into the group. This way, all the modifications from the rotational repeat will automatically apply to the circle. I found this to be quite useful.
I finished off the design by creating a few more circle patterns by copying them with “Alt+drag”. This also automatically copies the rotational repeat modifier.
I wanted to experiment with the parametric design possibilities within Cuttle. I wondered if I could arrange the pentagram and the folding flaps in a way that when I increase the number of sides of the pentagram, the flaps would adapt to the new polygon shape. For this, I created a universal parameter called “sides_param”. Then I wrote this parameter instead of a numerical value to “polygon sides” and “no. of repetitions”:
However, I did not account for the fact that there were no constraints between the polygon and the rectangle. Both components are positioned in the space in relation to the origin point. They were not defined by any sort of connection to each other, a constraint that relates them to an element of the other. Because of this, the following happened:
After messing around with the settings a bit more, I could not find a solution to this in a short time on my own. However, I found a few tutorials that explain thoroughly how parametric design works in Cuttle, which I will be exploring in the coming weeks. The parametric side of Cuttle is what interests me the most about this software, and I want to learn it and use it soon.
However, with not much time to spend on it left for this week, I moved on to explore other programs.
Photopea is a free online photo editor similar to Adobe Photoshop. I chose it as the raster software I was going to explore this week, because I had been thinking of switching from Photoshop for a while now. I searched online for a few tutorials, but the Photopea UI was quite familiar due to it’s resemblance to Adobe PS so I found it quite easy to navigate without relying solely on the tutorial.
I found this tutorial explaining how to remove background from photos. Since this is one of the things I frequently do on Photoshop, I decided to try it out in Photopea as well.
I placed a picture I had on my computer, and rasterized it by right clicking on the layer and selecting “Rasterize”. Then, I selected the “magic wand tool” to remove the background. We can adjust the “Tolerance” value in the upper toolbar until we get a selection we are satisfied with. By holding shift and clicking, we can add areas to the selection.
At this point, we can delete the background. However, if we want to potentially be able to make further edits, we should make a raster mask instead. Firstly, we make sure everything outside the subject is selected. Then, we inverse the selection by going “Select > Inverse”. We make sure that the subject’s layer is selected in the layer menu on the right. Through the bottom right toolbar, we click “Add raster mask”.
To clean up the remaining residue, we use the brush tool but make sure the raster mask is selected in the layer menu. Then, we can make finer adjustments with the brush. If it is black, it removes pixels. If it’s white, it adds pixels. You can use this to work on details by making the brush size really small. Or, you can brush off the outside with a bigger brush size to make sure there is no residue left.
If we have an image with hair, fur, or other similar features that are hard to distinguish from the background, we follow another method. For this cat image, we first make a rough selection with the magic wand. This time, we select the subject instead of the background.
In refine edge workspace, when we paint with black on the left, it removes pixels from the right image. If we paint with white, the opposite. When we paint with grey, Photopea adjusts the areas in between. Such as the feathered edges. We make the selection. When it is done, we select “New Layer” and “OK”.
I added a background with the “paint bucket” tool and some text with the text tool. Here is the final amazing composition.
