Monday, September 3, 2012

A visualization of how moisture affects wood

You have probably seen it already in Information Aesthetics: Two researchers from the University of São Paulo, Luis Carli and Rafael Passarelli, have developed Wood Changes, a visualization of the dimensional changes of different kinds of wood depending on the moisture level in the environment.

These interactive graphics probably won't appeal to a very broad audience, but they are intriguing and technically well executed, and their interface is inspiring. As I am interested in infographics and visualizations that don't come from the US or Europe, I asked Luis about how they came up with this idea, and what the creation process was. He sent me plenty of material.

First of all, here's the introduction to the project, taken from its website:

"Dimensional changes due to moisture exchange in wood can lead to defects, such as warping, checking or splitting, that may compromise the performance of the wood piece or product. Hence, most of the challenges of utilising wood in architecture or engineering involve understanding wood-moisture relationship and its influence in wood properties. This work intends to provide a more comprehensive form for visualising how different climate conditions influence different wood species regarding their dimensional stability. Nevertheless, it also aims to provide a design tool for most wood-workers (from architects to cabinet-makers) that could quickly estimate the behavior of some wood species in a specific location along the year and, then, implement necessary design modifications in order to accommodate dimensional changes."

And here's Luis' answer, including several hand-drawn sketches they made:

I developed the project together with an architect researcher from my University (USP), Rafael Passarelli. After he saw some of my works he came to me with some data about variation in wood size according to temperature and moisture.

He said that normally when designing something with wood, a furniture or a house, the designer needs to know how much the wood can change in size during the year, or how much it can change in size from its green state to a equilibrium with the environment, so that he can consider this variation in his project.

The problem is that the available data in the books and studies that we could find only showed the maximum amount a wood species could change in size, or how to calculate a size according to a certain temperature and humidity. But they didn't show how the wood changed along the year according to the weather of a city.

We thought that this data could be important when designing and constructing using wood, as according to the month of the construction, the wood could only grow or shrink. Also by visualising these data we thought it would be easier to understand and teach the relationship between temperature, humidity, moisture content on the wood and its size variation. The data that he showed me was only on tabular form.

We started by getting historical weather data from some cities, calculating the variation and plotting it, we ended up seeing bigger amplitudes and differences between cities than we had expected. From there I went on iterating and testing designs and user interfaces variations, the objective was to develop an interactive visualisation that could both teach about wood and be used as a tool to visualise the variations. The tests and the final version used the d3.js Javascript framework.

One interesting point is that I created a data structure to represent and operate the graphic design of the visualisation, so that I could prototype and test variations using relations between grids, spaces and positioning from the graphics elements according to my own mental model.  (I plan to write a paper about this topic).

Here are some of the sketches that I made during the development of the project: