Assignments
computer-controlled cutting (Feb 6)
Regular Polyhedra. Platonic Solids
Within the laser cutting exercise I perform a practice to bring 3D geometry to
schoolchildren in Seville.
Geometry, spatial vision, the concept of the three-dimensional display is not welcomed
because of new technologies (film, television, video games). Educational programs have
not assimilated this concept until an advanced age and curricula already directed
towards technical studies.
The purpose of this practice, focused on the development of Computer-Controlled
Cutting and regarding my final work is focused on the development of the five regular
polyhedra exist: hexahedron, icosahedron, dodecahedron, octahedron and tetrahedron.
This practice is aimed at children aged 10-14 years, an age where no special requires
geometric knowledge in schools, but the kids interested and want to start learning more.
In design practice, a historical approach allows children to know that regular polyhedra
were known in ancient Greece. Com that Plato used symbols of his philosophy, and
each represents earth, air, fire and water, combining the tetrahedron to the fifth element
or spiritual entity.
I get to practice with children who talk philosophy and mathematics, but without being
heavy for them.
The amount of software to represent geometric figures is wide. In Andalusia schools
students have computers running Ubuntu which include this software. But for the
development of this practice is better than software suits Fab Academy.
In the example shown in the image, use the golden rectangle to generate an
icosahedron from Rhinoceros. It is a quick exercise to show students.
The development of laser cutting exercise I have chosen the program Inkscape, which
helps with your clone tool to play with the tabs and get a correct fit of the faces of the
polyhedra.
In developing the model, the part that I'm most happy is the union of the edges,
developed to serve in the construction of all regular polyhedra, preventing exists a model
for every angle, all being in the same room , saving material and space for a more
elaborate design generate a wrapper that allows to keep all the pieces together to store
or move.
The circular piece is marked in each angle corresponding to each polyhedron and
facilitates assembly of the final model using the following numerical relationship:
Piece nº 1. Tetrahedron.
4 faces (equilateral triangles).
4 vertices. Common point of three faces.
6 edges. Concurren three at each vertex.
Dihedral angle of 70 32 '.
Piece nº 2. Cube.
6 guys (cuadrados).
8 vertices. Common point of three faces.
12 edges. Concurren three at each vertex.
Dihedral angle of 90.
Piece nº 3. Octahedron.
8 faces (equilateral triangles).
6 vertices. Common point of four faces.
12 edges. Concurren four at each vertex.
Dihedral angle of 109 28 '.
Piece nº 4. Dodecahedron.
12 faces (regular pentagons).
20 vertices. Common point of three faces.
30 edges. Concurren three at each vertex.
Dihedral angle of 116 34 '.
Piece nº 5. Icosahedron.
20 faces (equilateral triangles).
12 vertices. Common point of five guys.
30 edges. Concurren five in each vertex.
Dihedral angle of 138 11 '.
Modelo preparado para corte:
During design development, the main problem I had was choosing the sizes of the tabs
and their number per edge. I chose 3 mm MDF material to cut and started designing
parts with two tabs per edge. These two faces are oversized for the final result, so
eyelashes went from two to one per edge.
The result is a pattern of regular polyhedra physical representation that allows the child
to play with their mounting, known characteristics of each (sides, edges, angles, corners,
etc.) and be the beginning of the spatial geometry designed by computer.
Algunos ejemplos de las piezas terminadas:
To improve the design:
- Container box and engraved on the faces of the polyhedra characteristics and number.
- Increased size of the faces.
Software used:
- Photoshop.
- Inkscape
- Gimp
- Rhinoceros
- sketchup
Juan Carlos Pérez Juidias. Fab Lab Escuela Técnica Superior de Arquitectura de la Universidad de Sevilla