Incredible 3D printer bridging ability

This is a RepRap MendelMax printer built by UBC Rapid, a University of British Columbia student engineering team. For more information on UBC Rapid, see this link http://www.ubc-rapid.com/blog/ This video demonstrates how 3D printers can bridge gaps to create 3D objects without support materials. Shorter gaps can be bridged more quickly and more accurately than longer gaps. Shown here is an extreme example of bridging which demonstrates the versatility of open source RepRap 3D printers. Here is the final product http://i.imgur.com/XgKcXjg.jpg . The bridge span is 75mm (~3in) and I've included a 3D printed Lego compatible block for size reference. Here's a closer image of the top of the bridge http://i.imgur.com/XQk7EXX.jpg . Keep in mind that this is a torture test designed for the sole purpose of pushing the limits of our printer's bridging capability. It's not meant to be a practical piece, but it demonstrates the potential for long distance bridging. If anyone is interested, here's a random selection of printed items http://i.imgur.com/VCmdNgg.jpg that I could find lying around the lab. Our team has printed these over the last couple of months. There are several practical pieces such as the turbine, gears, mecanum wheel, cable chain and extruder carriage. The material being extruded is a thermoplastic called PLA, which is biodegradable and inexpensive. Credit goes to triffid_hunter for designing the bridging 3D model which can be found here http://www.thingiverse.com/thing:12925 . The model shown in this video is scaled to 150% normal size. Printing speed was slowed to 5mm/s for the purpose of the demonstration. With sufficient cooling, bridging speed can be safely increased by an order of magnitude.