Introduction: Key Crack Activity

About: Ngo active in the field of digital mediation, based in Toulouse, France

In this activity, kids will have to design and subsequently produce a key that is capable of accomplishing a 360° rotation inside a 3D printed keyhole

The key will need to look something like the one depicted in the image above, and will need to have a certain size (length, width) as well as specific features.

Age range 9-15 Skill level Beginner Objectives kids learn how to model a small object on tinkercad or how to produce it via a 3D pen kids practice basic logico-mathematical reasoning Background knowledge and competences basic knowledge of 3D modeling on tinkercad, basic geometrical skills (measure a length, etc.) Duration of the activity about 40 minutes Material and equipment needed A computer with an internet connection a 3D printer or a 3D pen some measuring tools (to measure lengths) paper and pencils to sketch some drawings

Step 1: Activity Plan

Activity Plan

Set up an account on

Enter this address on your web browser

Personalize the key crack design.

For example you may change the color

You may modify the size:

or add extra details, for example some text

Step 2: Preparation 3D Print the Design

Click on Export

and choose either obj or stl

Have the kids produce a key
The key must be designed in such a way as to allow a 360° rotation inside the 3D design. Kids can produce the key either on tinkercad (it will need to be 3D printed afterwards) or via a 3D pen.

To figure out the correct size of the key, they will need to observe the size of the 3D design

To do so on tinkercad, select the measuring tool

and place it anywhere on the plan
After that, just left click on the object whose size you would like to measure

Step 3: Find a Place to Print the Objects

If you are looking for a fablab where to print the items for the key crack activity, take a look at the map.