Let me hear your vox

For nearly two weeks now I’ve been working on a voxelizer, to convert a 3D model into an image that can be displayed by LitSpin. The goal of voxelization is simple: we need to display an image on a grid of leds, which means that the input image needs to be divided into voxels (3D pixels), each voxel representing a led.

Our grid looks like this:

The number of voxels corresponds to our desired resolution (20 circles, 128 angles and 32 leds from top to bottom).

The voxelization algorithm consists in tracing rays across the model to detect intersections with the triangles of the model.… Read more

Taking full control on our 3D model

We discussed in our post Generating 3D Models  the script I wrote to generate the 3D model of our phyllotactic sculpture. In this script, I start by generating a polyhedron made up of quadrilaterals arranged in a phyllotactic pattern:

Then, my script takes as input a 3D model of a petal and copies it on each quadrilateral:

The 3D model of the petal I use is taken from John Edmark’s model

One problem with this method is each quadrilateral is different, which means I had to slightly deform each petal to fir the quadrilateral’s shape. Figuring the exact 3D transformation to accomplish this seemed a little too time consuming so I used lattices in blender, which are a way to deform objects according to a 3D grid.… Read more

About LEDs

First ideas

Our original idea was to place LEDs on the inner sphere of the sculpture, either with flex PCB, or by drilling the sphere, placing the LED in the holes and connecting them with wires to a rotating PCB contained into the sphere. To facilitate the positioning of the LEDs, we could have modified the design so that we can pin the petals one by one on the inner sphere rather than print everything in one block.

But these designs are not easily achievable. First, Alexis does not know how to design flex PCBs. Second, to have a satisfactory visual impression, we would like to have at least 100 petals.… Read more

Generating 3D Models

TL;DR

  • We need to generate 3D models of phyllotactic patterns.
  • We give an explanation of how to generate phyllotactic patterns on a sphere.
  • We present an issue we encountered, and the solution we found.

Why 3D Models ?

When we first started thinking about the project, we quickly realized we would need to generate 3D models of the sculpture ourselves.

First because we need to have full control on the model, to try various configurations for the future 3D printed sculpture. And second because it will greatly help us visualize all the kinds of animations we are imagining.

Accordingly, Vlaya wrote a script using the blender python API to generate a 3D model, following John Edmark’s online explanation.Read more