http://youtu.be/YlCQcwxTRfc?list=PLuzXmzWDJs5DtoNdg3rSR-rRPnVcGr25L
Physics-based - all computations regarding lights, whether natural or artificial, as well as all materials, their definitions and properties, are not emulations or simulations but designed as algorithms based on the real and natural world. For example, artificial lights use IES standards and Lumens as units; the Sun's setting depend on time, day, geographic and environmental conditions such as types o cloud or fog; cast shadows are not set as "soft" or "hard" but are produced according to actual lighting conditions; materials behave as expected according specific properties and types of finishes...
Real-time - depending on the hardware (required an nVidia GPU with a minimum of 500 CUDA cores) and on the complexity of the model, the software responds interactively - the user suffers no wait-time or latency allowing to make design decisions regarding lights and materials on the fly, moreover what you see is always what you get, meaning that the quality of the output depends on user...
Hardware scalable: the more and the better the GPUs, the faster results. Unicorn is the only application in the market, so far, that use a local rendering mode or can handle a remote server, render-farm, with four or more video cards...
Finally, Unicorn is a rendering compositing tool: it supports the import of up to 45 different file-formats: simply drag and drop into Unicorn a file from Revit, SketchUp, MoI/Rhino, Maya, Blender, or, etc. The user can edit in the native 3D modeling application any of the models and simply re-import it; Unicorn retains the material settings already assigned to the original geometry thus updating the composition, again, in real-time...