## Foam 3D

### Quick Start

It can be hard to visualize a foam, so here we explore it as a Kelvin Foam in 3D. Use your mouse to move around outside and inside, use the two controls to adjust the visual properties.

### Credits

This uses the newer Three.js infrastructure and a VR version will become available.

We have 15 bubbles assembled into a small subset of a large volume of foam - you can imagine other bubbles extending out further. The bubbles are tetrakaidecahedra (14 faces), also known as truncated octahedra, with 4- and 6-edged faces and are one of the Archimedean solids. They are able to tesselate, to fill space. Lord Kelvin pointed out that they made a good approximation to an ideal foam, and so this foam is called a Kelvin foam. A more perfect foam was defined by Denis Weaire and Robert Phelan, but the Weaire-Phelan foam (made of a dodecahedron and a different tetrakaedecahedron with a mix of 5- and 6-edged faces) is harder to visualise. Despite the kind help of Guy Inchbald, an expert in 3D shapes, I decided not to implement one because for our purposes, the Kelvin foam is good enough.

To get a feel for what a foam is, use your mouse to zoom in, rotate (left click) and pan (right click) so you can see the foam from whatever angles interest you.

### The three key features are:

1. The foam faces or film walls. They make up the bulk of the surface area of each bubble but account for a tiny % of the foam material.
2. The Plateau borders. These run along the edges of the foam faces and contain a large fraction of the foam material. Foam drainage runs through these borders. The shape of the borders are curved triangles in cross-section. I can't create the exact form but when you zoom in you see some triangular cross-sections to remind you.
3. The nodes. These are where the Plateau borders meet.