# 3. Computer Aided design¶

This week I worked on designing and 3D modeling an electronics housing for my final project. The plan is to house the micro-controller board, relays, screen and keypad in one housing component. it will take a rectangular shape with sliding lid to cover it up and it has two holes for the wires to pass through. I will be using BS Dasault SOLIDWORKS for all my 3D modeling related work/assignments.

solidworks window.

## Raster Vs Vector¶

In order to design a 2D image, it is very important to know that there are two types of image format:

The raster format (jpg, gif, png…) The vector format (ai, eps, svg…) The main difference between these two formats is that a vector image can be enlarged without losing its quality, whereas a raster image loses its sharpness when enlargedthus it appears blur.

The raster image (or bitmap): It is composed of small points called “pixels” that we do not see with the naked eye. When a raster image is enlarged, this image is no longer visible to the naked eye. When a raster image is enlarged, it becomes blurred because the pixels come out, these are the squares that appear on the screen.

The vector image: It is composed of lines of segments that are linked together by mathematical formulas. It is a system of proportionality and coordinates. Thanks to vectorization, each element has a well-defined place which prevents the image from being distorted.

The image below shows a side-by-side commparison of the two types of images at 1x zoom and at 4x zoom respectively

## Using Inkscape¶

You can get the windows x64 version of the Inkscape software here. The installation is pretty simple and complications-free. So I decided to make a simple 2D model of “NASA” Writing using Inkscape, below you will find screenshots of the installation process and my sketch.

image: screenshot of the installation process

image: the welcome window of Inkscape where you make your preferred settings and choices

image: the blank drawng space window, this is where are sketches can be made

imgae: in this picture I used the draw bezier curves and straight line command and the draw free hand line comand to draw this NASA

image: I used the draw caligraphic or brushes stroke comand to create the deep lines in the NASA drawing.

### Step 1 - 2D sketches¶

I generated the base sketch in 2D using the rectangle command on the front face plane. I then dimensioned it according to my specification.

### Step 2 - 3D modeling¶

After the 2D sketch, I extruded the sketch to give the base model

Then I used the shell command to make the base model hollow to accomodate the electronic components.

I used the cut estrude command to create holes for the passage of the wires into and out of the components housing.

I used the extrude and chamfer commands to create the sliding grooves.

I worked on the lid of the electronic component housing unit using the various commands like, 2D sketch,extrude, cut extrude, fillet and chamfer.

## 3D files¶

These are the STL files I generated

Component housing

component housing lid

Now, I use Gimp 2.10 batch image manupulator software to compress and resize my images before I upload them on to my GitLab server

image: resizing

image: resizing

image: compression and format of the picture

After compressing the images I copy the necessary ones into my local folder and then Git push them when I am submitting the assignment.

Last update: July 5, 2022