Damn. That laser is something. It's a specially designed LasX proton laser art system that blasts a beam to make art at lightning speeds. The CAD file for the design, called After Sunset, was created by Andy Gikling and was imported to the laser control software and then zapped out onto the chalkboard to etch the design. How cool is that?
In the first part of the video the laser is "raster" processing. Raster processing is the laser equivalent of the old school ink-jet printer style of paper printing. Here the beam is sent left and right across the material at a speed of 20 meters per second at a vertical repeat spacing of one pass per pixel in the image. The grey level in the image is mapped to the laser's power output on the fly. This is how the chalkboard yields different levels of grey — we're damaging the paint with just the right amount a power to get the affect. Fortunately, the Lightguide v5 software running with our Proton laser controller affords us such control. Parameters like laser beam speed, focus spot size and lines per inch are critical here.
The second part of the video shows the software "vector" processing the piece. In this mode the laser beam follows the vectors defined in the PDF file. The geometry is perfectly aligned with the raster part of the image. A beam speed of 6 meters per second was shown. During this process the laser is outputting nearly 1500 watts of power. This causes the cuts to go through the paint and into the wood behind it — leaving an orange and brown colour. The reason the vectors follow such a strange order across the piece is because a simple "proximity sort" was performed in the Lightguide v5 software before processing.