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3. Computer Aided design

Assignment

model (raster, vector, 2D, 3D, render, animate, simulate, …) a possible final project, compress your images and videos, and post a description with your design files on your class page

3D file :

Corps guitare igs

Tutorial on how to use fusion 360 :

Fusion 360 bascics

Gantt plan of the week

Compressing files

Videos

I’m planning to compress videos with ffmpeg tools :

I started with this tutorial.

As a novice programmer, I would recommend to install from gyan.dev to get an executable file and not a source code.

In advanced system parameters, do the following :

Go to environment variables Add ffmpeg to the path

Then, I enter the code line from this page

First, we need to verify if ffmpeg is well installed :

ffmpeg version

You should see this :

Then, I tested the following code lines to compress videos :

ffmpeg -i input_video -vcodec libx264 -crf 25 -preset medium -vf scale=-2:1080 -acodec libmp3lame -q:a 4 -ar 48000 -ac 2 output_video.mp4

ffmpeg -i input_video -vcodec libx264 -b:v 1000k -vf scale=-2:1080 -acodec mp2 -b:a 256k -ar 48000 -ac 2 output_video.mp4

For a file of 14.7 Mo, I had the following results :

variable bit rate 1080p MP3 fixed bit rate 1080p MP2

So the fixed bit rate 1080p MP2 has a better compression rate.

Pictures

For screenshots, I’ll save in jpg instead of png to save space.

I’m compressing pictures with GIMP. The function to export under allows to change the quality of image :

To make gifs I use this site. It allows to optimize gifs in order to reduce its size :

Size of the folder of this week :

Model of the final project

Here is my to do list for this week assignment :

  • Create a body for the guitar with xDesign

  • Insert emplacement for the neck of the guitar

  • Insert cuts for the bridge

  • Insert cuts for the pads + LCD screen + switches

  • cuts for the jack wire

  • 3D models of pads and LCD screen

  • 3D model of the bridge

  • Optional: 3D model of the neck

First I made a sketch for basic dimensions :

I plan to do the 3D model on xDesign to see the functionality of this software. First I made a basic angular shape, fillet to round the angles and all the cutting dimensions :

Then extrusion for the top surface and body :

Here is the 3D model :

Dita's Gown by Francis Bitonti Studio on Sketchfab

For the rendering, it seems that xDesign doesn’t have any option for it. So I exported the shape in .igs in Fusion 360.

You can check this page to get the basics of fusion 360 manipulations.

Model of pads, screen and neck

to do…

Comparison between CAD softwares

For this week’s assignment, under the guidance of my instructor, I want to do a brief comparison between softwares to do a gear shape and make my mind about which one is best for this.

Modelisation

Fusion 360 Rhino


What does best Fusion ?

Fusion proposes a historic of conception which allows to change operations made in the past



There is also the possibility to design parametrically in an easy way


What does best Rhino ?

There is a command line which can make any operation fast. There is also an option to work with layers

Rendering

Fusion 360 Rhino
Fusion offers different parameters to render something : Possibility to edit the background environment : I choose here to edit the material : You can also edit the luminosity, colour… :
Here is the result of the rendering with Fusion 360 : 		Rhino offers different parameters to render something : Possibility to edit the lighting : I choose here to edit the colours according to the layers : You can also edit the colour, background… :
Here is the result of the rendering with Rhino :
Thoughts on xDesign vs Fusion 360 vs Rhino

xDesign has limited options compared to what I could do with CATIA and even compared to fusion 360. And the fact that we are using it from the web make it really slow to work with.

Fusion has a good simple interface and the historic aspect is great. Fusion is more straight forward regarding rendering.

Rhino is powerful to make fast design and has good surface tools. It is less good for setting and changing dimensions easily. Rhino seems to offer more possibility to customize the rendering.

2D Vectors Programs

I also did a brief overview of Inkscape. I started by looking to tutorials to see the possibility offered by the software.

I want to draw the image on the frets of the neck of the guitar.

First I had to check the mathematical relation for the spacing between each fret. This formula is directly related to the wavelengths and the frequency of notes. I used an excel (open office calc) document to calculate it for the 21 frets.

Here you can see how I drew them on Inkscape using the Y position of each fret :

Then I made a few drawing :

And here, you can see the images on the fret board :

Cutting a segment in Inkscape
  • Select the nod edit tools

  • Use CTRL + alt to place a nod on each extremity of the segment you want to cut

  • Then click on the following icon to break the path between nods

  • Then suppress the segment

Last update: June 27, 2022