Projection mapping is a really cool way to create visual effects that almost look like magic. The basic concept is that you use a projector to display some sort of graphic or video on a real world object. When it’s done well, the projection is lined up with the edges and curves of the object to make it come to life. The technique was used on the Sydney Opera House, for example, and the results were pretty amazing. If you want to experiment with projection mapping yourself, Projectile Objects has a write-up that explains how to get started with a Raspberry Pi.
The key to projection mapping is software that distorts your graphics or video to match the surface you’re projecting onto. Without that calculated distortion, the projections would look skewed from every angle except where the projector is. The software lets you replicate the angle and shape of the projection surfaces so that the visuals look how they should: covering the entire surface, but only that surface, and without visual distortion.
To do that properly, you’re going to want projection mapping software, and Projectile Objects compares three popular options. ofxPiMapper is a free, open source package that comes in the form of a SD card image tailored specifically to the Raspberry Pi. miniMAD is a rather expensive option — $220 for the pre-built Raspberry Pi device and $420 for the required Madmapper software — but it seems to be highly polished. PocketVJ is another open source option that’s built on ofxPiMapper, but which integrates some handy control panel features that are accessible from your smartphone.
Projectile Objects does a great job of explaining the pros and cons of each package, and how to get started with them. If you’ve got a Raspberry Pi and access to a decent projector, their article is where you should start if you want to get into projection mapping.