2. Computer-Aided Design¶

This weeks goal was to evaluate and select suitable 2D and 3D design workflows for my final project, create design files, and document the results.

2D Modeling¶

pixel-based¶

An image is represented as a grid of individual pixels, where each pixel has its own color value. The quality depends on the resolution (pixel per unit). When scaling up or zooming in the pixels become visible and edges appear blurred. Nevertheless raster graphics are best suited for photographs and detailed images with complex color gradients.

The typical file formats are:
PNG, JPG/JPEG, BMP, TIFF, GIF

I compared several programs and would like to highligh two:

Criterion	GIMP	Microsoft Paint
Type	Raster graphics editor	Basic raster graphics editor
Target group	Advanced users, designers	Beginners, quick sketches
Layers	Fully supported	supported
Image editing	Very extensive (filters, masks, retouching)	Very limited
Color management	ICC profiles, precise color control	Minimal
Automation	Scripting (Python, Scheme)	Not supported
Platforms	Windows, macOS, Linux	Windows
Typical use case	Image editing, documentation, photo retouching	Quick annotations, simple drawings

GIMP is a fully featured image editing tool. Paint is only suitable for basic image manipulation.
I will use GIMP because it supports image editing, color control advanced workflows.

Download

vektor-based¶

Instead of pixels, mathematical descriptions define the points, lines, curves and shapes on a cartesian plane. Vector graphics can be scaled infinitely without any quality loss. It is fundamental for digital manufacturing.

Check out Vector graphics on Wikipedia for more information.

The typical file formats are:
SVG, DXF, AI, EPS

I compared several programs and would like to highligh two:

Criterion	Inkscape	Adobe Illustrator
Type	Vector graphics editor	Professional vector graphics editor
License	Open source	Proprietary (subscription-based)
Target group	Makers, FabLabs, open-source community	Graphic designers, agencies
Native file format	SVG	AI (native), SVG
Precision	Very high (nodes, paths)	Very high
Text and path tools	Extensive	Very extensive
CMYK support	Limited	Full
Extensibility	Extensions (Python-based)	Plugins
Platforms	Windows, macOS, Linux	Windows, macOS
Typical use case	Laser cutting, vinyl cutting, diagrams, logos	Branding, print design, illustration

Adobe Illustrator offers more advanced features for professional print workflows. Inkscape provides precise path control and compatibility with digital fabrication trought extensions.
I will use Inkscape because it is a well suited vector based program for this use case. Adobe Illustrator offers advanced design features which are not required for FabAcademy fabrication tasks but it remains an enourmous program.

Download

3D-Modeling¶

Objects are represented in three-dimensional space. Geometries are defined by vertices, edges and faces. The objects can be created as bodies, surfaces or meshes, while each type allows parametric or direct modeling. 3D models are used for digital fabrication, visualization or simulation.

The typical file formats are:
STL, OBJ, STEP, IGES, 3MF

I compared several programs and would like to highligh two:

Criterion	Autodesk Fusion	TinkerCAD
Type	Parametric 3D CAD software	Browser-based 3D modeling tool
Target group	Engineers, makers, product designers	Beginners, educational use
Modeling approach	Parametric, surface and solid modeling	Primitive shape-based modeling
Assemblies	Supported	Not supported
Simulation	Structural, thermal, and stress analysis	Not supported
CAM / CNC	Integrated	Not supported
Export formats	STL, STEP, IGES, DXF, and more	STL, OBJ
Learning potential	high	low
Platform	Windows, macOS	Web browser
Typical use case	parametric design, assemblies and fabrication-ready models for CAM	educational exercises and quick concept visualization

TinkerCAD is easy to use and the web browser-based design makes it perfect for educational purposes and first touches with 3D modeling. Autodesk Fusion combines design, simulation, manufacturing (CNC, 3D printing), and data management in a single application, enabling collaborative work and parametric modeling.
I will use Autodesk Fusion because it provides parametric modeling and full history control. The integrated CAM module is suitable for the local machines. Overall it provides a professional environment that scales from prototyping to production ready manufacturing.

Download

2D Project¶

Logo design with Inkscape¶

In this chapter, I will show you how I made a potential logo for my final project.

Create a new document.

This is the general overview of the workspace.

First I drew a circle with the tool and set the x- and y-diameter to 55 mm.

Then I drew some rectangles with different measurements.

Then I added more circles.

I positioned the rectangles along the y-axis.

Aligning all objects on the x-axis relative to the big circle (last selected).

Then I used some boolean operations to design a lamp.
Division between the little and big circle.

Intersection between the middle and big circle.

I added an ellipse.

And combined the previous created circles.

Then a division between the elipse and the combined circles.

To get this.

I deleted this part.

And just to make sure everything is still in place I aligned everything again along the x-axis.

I drew a new big circle (with the same measurements as before).

And aligned the lamp to the top corner of the circle.

Now every frame is set and I can start filling in the colors.
I added an gradient colour to the big circle. Note: Gradients may appear differently on different background colors due to their transparency.

I colored the light bulb in monochrome yellow.

And used the same yellow with gradient for the first rectangle.

With the gradient tool G I changed the direction.

And repeated everything for the other rectangles.

This is the progress so far.

I colored the lampshade grey.

And added a stroke paint to the big circle.

The design was finished.

I exported my logo as PNG.

SVG files are highly optimized, taking up less storage.

Image compression¶

To compress screenshots I used TinyPic for Windows.
All images used to document the Inkscape workflow summed up to 5,8 MB but after compression, the FabAcademy server only has to handle 1,5 MB! This reduction makes a big difference of 75% and helps avoid ending up in the “Hall of Shame” for having the largest repository.

3D Project¶

Lamp design with Autodesk Fusion¶

For better visualization I designed a 3D model for my potential final project. Afterwards I rendered a short video and an image.

This is the general overwiev of the workspace.

First, I created a sketch.

And choosed YZ plane.

The line tool is useful for many cases.

I started with a 2 mm edge.

From there, 30 mm with 45°.

The top plane has a total length of 400 mm and I finished the shape.

I used the build-in feature to track the midpoint and drew a 25 mm line.

And another guideline, now 50 mm.

By dragging from top left to bottom right, the selection mode only selects objects fully covered by the selection.

I used another guideline for the height of 1250 mm.

And 400 mm along the Y-axis.

One line appeared blue, therefore I checked for missing sketch dimensions.

I used the spline tool to draw a spline between the guidelines.

Then I copy-pasted this spline and moved it -50 mm in both axes.

And finished the shape with this line.

Then I trimmed T every uneccesary part.

And added a support only on two sides.

Then I finished the sketch.

And continuied by extruding this plane 40 mm.

For the base I chose 200 mm for both sides.

With the fillet tool, I rounded the other two corners.

Then I realised my mistake with the base. However, editing past actions is no problem.

By right-clicking the symbol in the timeline, I fixed my little miscalculation.

Then I used the shell tool to get a feeling for how thick the lamp can or has to be to remain stable and to provide enough space for all electronic parts.
In the end I choose a 9 mm inner thickness.