3. Computer Aided design¶

This week I worked on 2D and 3D modeling my final project with : Inkscape, Paint (2D), Autodesk Fusion 360 and Blender (3D)

2D modeling with Inkscape¶

Design thinking¶

The first step was to think about the design of the product regarding its use. As I want it to measure the force exerted on the dog leash, it needs to be placed where the force sensor can work. I get inspired by a horse rein tensionmeter called EC-Hand Tensiometer that I saw on the website “epplejeck”. The force sensor needs to be in contact with its 2 ends to the leash to measure the tractive force as in the “EC-Hand Tensionmeter” below. I’ve annoted the different strengths in orange with windows 11 image tool that allows to annoted the picture with the computer touchpad.

Image modified from the site Epplejeck presenting the EC-Hand Tensiometer

Then I checked a dog leash product to amortize the impacts of dog pulling on leash, called Yangbaga that I saw on “Amazon” and annoted with orange.

Image modified from the site Amazon presenting the Yangbaga anti-shock leash

It gave me the idea with the advices of my instructors to put the electronic tensiometer at the base of the leash to adapt with the collar or the harness and so be in capacity to measure the strength exerced on the leash. As figured on the picture below :

It means that there will be a carabiner at the collar/harness side and a stainless metal d-ring on the leash side.

Carabiner from pixabay

D-ring buckle from Joyce Trimming Inc

Now that I know better how will look my connected object, I can start the work of 2D modeling.

Inkscape¶

The final result :

The different steps :

Download Inkscape
Open Inkscape
Download a carabiner picture from pixabay
Import the picture to Inkscape
Make a rotation of the image with “ctrl” and “[“
Create an ellipse

Create 2 circles
Select the 2 circles and click on “path” > “difference” => a new form is created

Create another circle and do it again to finish the form

Create 2 triangles and move it to the new form

Remove the background of the triangle with the menu on the right

Select the 2 empty triangles and the form and click on “object” > “group” => all the select elements are now one unique piece

Move it on the ellipse, click on the left menu on “edit nodes” and move the right side on of the triangle to follow the shape of the curve

Which leads to that :

Then add rectangles, create the D form with the Bezier curves, add circles and change the color with the menu on the right

Finally, add some text by clicking on “extensions” > text > replace the font

Paint¶

I did a rabbit sketch on Paint.

I modified the type of pencil, the size and the color :

3D modeling with Autodesk Fusion 360 and Blender¶

Autodesk Fusion 360¶

I drew the outer box of my connected object and a carabiner that would go on the box.

Final results :

That’s the render of the improved carabiner :

Download Fusion
Open Fusion
Click on sketch
Choose a plan
Click on created and choose ellipse
Centered the ellipse, design it and click on “finished the sketch”
Click on extrusion to add volume
Enter a positive value if you want to add volume an a negative value if you want to remove volume
Add a tangent plan to the ellipse by clicking on “build” > “Add tangent plan” (but it didn’t work so I aborted this shape)

Design a rectangle by clicking on “sketch” > “choose plan” > “created” > “rectangle” > “rectangle by the center” and then rounded corners with the tool surrounded with orange

As I didn’t like the shape I started again a new sketch by forming a rectangle with 2 semicircles formed with the “arc” tool in “created”
Then Define the width at 50 mm and the length at 150 mm
Define the height : 50 mm with the extrusion tool

Make the old sketch visible by clicking on the crossed eye on the left menu and select the all to click on “combine” to make it one
Make a circle on a face and then make a negative extrusion to make a hole for the USB port
Add 2 tangent plans at the extremities and create two circles
Then I did a carabiner
First : create a sketch with the “line” tool and design all the carabiner
Then : make a curve with the filet tool and play with the different angles to get those you want

Make an extrusion of the parts you want
Make sure you put the same size
And that’s all !

For the improved carabiner more steps were needed. The piece was made with different sketchs that were then merged.

Render¶

Go to the render mode :

Move your object until you get a nice plan and click on “render” :

Animation¶

Here is my carabiner animation :

Carabiner video (.avi)

I did it with the animation function in Autodesk fusion 360.

Create a scenario
Select the components you want to make move
Transform it with the moves/ rotations you want

Change the timing or the order of the moves as you want
You can also make it ends as it began by clicking on “transformation” > “restore the view to the beginning”

Blender¶

Download Blender
Open Blender
Delete the cube by selecting it and press “delete” on your computer
Click on “shift” + “a” to add a new form
Move your new form by clicking on it and then click on the “transform” button on the left and then move the different circles and cursors to make it bigger/smaller or just move it

You can zoom with your touchpad or by clicking on the “+” button on blender screen
If you want the shape to merge you need to move it very close and a merge should be created automatically
If you want to change the plan, you can click on the different “x”, “y”, “z” axis at the right of your screen

Files¶

I added my files by exporting it from Autodesk Fusion 360 to : “git > site > docs > files” :

Useful links¶

Last update: April 4, 2022