Week 2 - Computer-Aided Design
Published on: February 4, 2025
This week, I explored various 2D and 3D modeling software tools to understand their features and applications in digital fabrication. The goal was to get hands-on experience, test different software options, and evaluate which ones best suit my needs for future projects.
Exploring 2D Design Software
GIMP – Open-Source Image Editing
GIMP is a powerful and versatile raster graphics editor that serves as a great alternative to Photoshop. It is widely popular in the Linux community but is also available for Windows and macOS.
Upon launching, GIMP greets you with a clean and professional interface.
Creating a new file is simple – just go to File → New, where you can define the canvas size and resolution.
GIMP provides a range of useful templates and allows users to customize resolution settings.
It supports multiple layers, making complex image editing more efficient.
Additionally, GIMP includes advanced brush settings for digital painting and fine adjustments.
Inkscape – Vector Graphics Editing
Inkscape is a widely used vector graphics editor, perfect for creating designs for laser cutting and vinyl cutting.
Downloading and installing Inkscape is straightforward from the official website.
One of Inkscape's standout features is its ability to convert raster images into vector paths using the Trace Bitmap tool.
Here's a zoomed-in comparison of an original raster image and its vectorized version.
Once converted, the new vector image can be scaled infinitely without losing quality.
Exploring 3D Design Software
FreeCAD – Open-Source 3D Modeling
FreeCAD is a free parametric 3D modeler designed for engineering and product design.
It's available for multiple operating systems and easy to install.
The software also features a dark mode, making it more comfortable for extended design sessions.
Users can export models in different formats, supporting a variety of fabrication techniques.
Fusion 360 – Professional CAD Tool
Fusion 360 is a cloud-based CAD software that integrates modeling, simulation, and manufacturing tools.
The design process begins with sketching a 2D outline.
Basic shapes can be dimensioned and later extruded into 3D models. In the top left corner you can click on the field with the green plus to create a sketch.
This can then be used to create 2D sketches, which can then be transformed into 3D objects. For example, you can create a circle and enter the diameter in the field. You can then extrude this to obtain a 3D model. First, however, you must click on finish sketch.
You can now make a few settings in the menu and then extrude the object. We now have a cylinder.
Final Thoughts on 2D and 3D Modeling Tools
Both 2D and 3D modeling software play a crucial role in digital fabrication, each serving different but complementary purposes. 2D software like Inkscape and GIMP is essential for creating vector-based designs, which are particularly useful for laser cutting, vinyl cutting, and graphic design. These tools allow precise control over outlines, colors, and layers, making them invaluable for preparing fabrication-ready files.
On the other hand, 3D modeling software such as FreeCAD and Fusion 360 enables designers to create complex three-dimensional objects with accuracy and detail. FreeCAD, as an open-source tool, provides a versatile and customizable environment for parametric modeling, making it a great choice for mechanical design and engineering applications. Fusion 360, with its cloud-based integration and extensive toolset, is widely used for prototyping, manufacturing, and even generative design.
Mastering both types of software expands creative possibilities and allows for seamless transitions between different fabrication techniques. Whether sketching a basic concept, designing precise 2D cut files, or engineering a fully realized 3D object, these tools empower makers to bring their ideas to life. As I continue my journey in the Fab Academy, I look forward to refining my skills and integrating these tools into my future projects.
Modeling
2D-Modeling
One way to produce the bearing blocks for the drive of my final project is to design them in 2D and cut them out with the metal laser cutter. For this reason, I will first model the bearing blocks in Inkscape. For my final project, I need two bearing blocks, which accommodate a 13mm ball bearing and connect the two shafts to each other via a toothed belt. I therefore need a bearing block to which the stepper motor is attached and the drive shaft for the tires, as well as a counterpart that receives the drive shaft.
The dimensions should be 130mm x 60mm. I also need two recesses. One for the ball bearing and one for the motor shaft.
After I have drawn the first circle and entered the dimensions 6.5 mm radius Rx and Ry at the top, I draw the second circle with the diameter of the drive shaft. The Nema17 stepper motor has an outer shaft diameter of 8mm.
Next, I want to center the circles. To do this, I first mark all the elements.
Next, I use the align tool and select center on horizontal axis.
Now the holes with which the motor block is attached are still missing. The frame size of the Nema17 is 42mmx42mm. In the data sheet I found out that the distance between the screw holes is 31mm. In addition, M3 is used for the screws. I looked in the ISO thread table DIN 13, T1 and found that the through hole for an M3 fine thread is 3.2mm. So I draw 4 holes with the corresponding dimensions.
Next, I draw a circle with a diameter of 32mm around the elements for orientation.
The distribution tool helps to distribute the through holes accordingly on the auxiliary circle. Next, the circle that we needed to distribute the objects is deleted.
I group the elements so that they can no longer move in the future. A little hint: Unlike most programs, Inkscape uses Shift to select multiple objects.
When drawing, I noticed the error that the motor should not float in the middle of the bearing block, but must be placed at the bottom. So I move the group and save the file as .svg.
3D-Modeling
Next, I modeled the second bearing block in Fusion 360 3D. This has the advantage that I can simply print it out for testing and don't have to use so much aluminum for the first prototypes. I start by creating a sketch in Fusion and create a square measuring 600 mm x 700 mm.
Next, I press Finish Sketch to finish the sketch.
Then I extrude the cuboid.
The next step is to model the drill holes in the lower part of the block. To do this, I switch back to the sketch view, select the underside of the block as the basis and draw a guide line in the middle. I create a circle and would now like to have it on both sides of the block, which is why I mirror it on the auxiliary line.
After removing the auxiliary line, it looks like this.
Then I finish the sketch again and cut out the drill holes with the Extrude tool at a depth of 15mm.
The model then looks like this:
Next, we take care of the recess for the ball bearing. Since the ball bearing only has a depth of 5mm and we have a material thickness of 10mm, we have to draw a circle with 13mm and drill 5mm deep.
We want to leave a margin of 2mm. To do this, we select the same center point and draw a circle with a diameter of 11mm, which we then drill through to the full thickness of the material.
Our model for the bearing block is finished.
3D Modeling of the Final Project
The two parts of the final project shown here are only small components. At the same time, I tried to construct the robot in Fusion 360 for the first time.
I started with the construction of the base plate, in which I made two cut-outs for the wheels and four screw holes for attaching a 360-degree rotating wheel. I positioned 8 slots on the edge into which the 3D printed cover will later be inserted. I also added 4 threaded rods to connect the two plates together.
A second plate with the same slots and holes for the threaded rods was then placed on the threaded rods. The dome was then mounted on top of this and a compartment inserted.
File Compressing
Image Compressing
Another task for this week is to document how to compress files and optimize for web use.
ImageMagick is a powerful command-line tool that allows you to process and manipulate images, including resizing, converting, and optimizing them. It supports a wide range of formats, including PNG, JPG, GIF, and TIFF.
You can download ImageMagick on https://imagemagick.org/
To check whether the installation succeeded you can enter the following command in your cmd:
magick -version
Preparing Your Image Folder
Before resizing, ensure:
- All images are stored in a specific folder (e.g.,
input_images/). - You have created an output folder (e.g.,
output_images/).
You can create an output folder using:
mkdir output_images
Resizing
To resize all images to 50% of their original size run:
mogrify -resize 50% -path output_images/ input_images/*.png
Resize All Images to a Fixed Width
Resize all images to a fixed width of 800 pixels while maintaining aspect ratio:
mogrify -resize 800 -path output_images/ input_images/*.jpg
Convert all images to JPEG format while resizing them:
mogrify -resize 1024x768 -format jpg -path output_images/ input_images/*.png
This command: Resizes all images to 1024x768 pixels and converts PNG Files into JPEG format.
Video Compression with FFmpeg
To optimize storage and improve loading times, I compressed my video using FFmpeg. Below is the step-by-step process I followed.
1. Installing FFmpeg
First, I ensured that FFmpeg was installed on my system. I checked this by running the following command in the terminal:
ffmpeg -version
2. Compressing the Video
To reduce the file size while maintaining good quality, I used the following command:
ffmpeg -i .\original_video.mp4 -vcodec libx264 -crf 28 small_video.mp4
- -i input_video.mp4: Specifies the input file.
- -vcodec libx264: Uses the H.264 codec for efficient compression.
- -crf 28: Sets the quality (lower values = higher quality, 28 is a good balance).
- output_video.mp4: The name of the compressed file.
4. Comparing the File Sizes
After compression, I compared the original and new file sizes to see the reduction.
5. Verifying the Output Quality
Finally, I played the compressed video to ensure that the quality was acceptable:
