Interactive Sphere

December 18, 2010

This was a fun project calling for a custom interactive sphere video controller as part of a large permanent installation. The installation involved a large number of spheres with synchronized video projections. The “earth” sphere served as a controller for starting, stopping and selecting videos with a swiping gesture.

The rig consisted of a 6 foot plastic sphere with a hole on one end and a super-duper wide angle lens. The housing was pretty slick with a vertically mounted projector and mirror assembly along with computers for the graphics and video processing and cooling. Another hole was drilled into the sphere for the camera and IR lighting to do the finger tracking along the sphere’s surface.

I built a touch based calibration system to map the camera tracking coordinates to the camera viewable area of the surface.

To map the real-time generated content to the sphere I integrated a custom shader for distorting the geometry into spherical coordinates with tweakable edge distortion parameters. The information on Paul Bourke‘s site was indispensable.