3D Hacker has posted an interesting video interview with David Braam, the developer of Cura. What's Cura? It's a new 3D printing management program designed to drive the Ultimaker personal 3D printer.
Braam used his own Ultimaker for some time but noticed problems in the software environment, specifically around time delays. 3D printing is usually a very slow process, both in printing and the software to slice the 3D model for printing. He decided to do something about it and created Cura to overcome the issues.
Cura includes its own slicing engine, avoiding the generic open source Skeinforge typically used by 3D printer manufacturers. Skeinforge is horrifically slow to slice complex models. By replacing the slicing engine, complex model preparation time can transform hours into minutes. While it's "tuned for Ultimakers", it can be used on any RepRap-style machine.
Another time delay addressed by Cura is the delay occurring during prints of multiple objects. Normally the 3D printer must traverse the space between the objects on each and every layer, adding considerable time to the print. Cura solves this in a revolutionary manner: it can print each object in the print job separately in sequence.
Cura must have a very good understanding of the geometry of the printed objects as well as the printer itself, otherwise the extruder would crash into previously completed objects. There's likely some pathological situations where Cura cannot perform this feat, but for many prints this would be a massive time-saver.