When it comes to the realistic simulation of humans and humanoids, the realistic modeling of hair is one of the last remaining barriers. Thanks to the ever-increasing power of computer chips, and billions of dollars of R&D into human kinetics, gait analysis, and musculoskeletal biomechanics, we can now model the human body and face with superb realism. Hair, though, with its millions of interwoven and interrelated strands, is really difficult to get right. For the most part, male heroes are just given short hair, and females — despite a disproportionate amount of effort on behalf of the 3D artist — are usually stuck with a dull, lifeless hairdo.

Now, thanks to the work of Princeton and the University of Southern California researchers that will be presented at Siggraph 2013 in June, beautiful, bouncy, realistic hair could be just around the corner. At this point you should watch the video below.

Rather than being painstakingly drawn, or perhaps imported from some kind of high-resolution motion-capture tool, “Structure-Aware Hair Capture” (SAHC) takes just a few still frames as input. From these still frames, which are taken at different points around the human hair model, a 3D point cloud is created. Orientation data (where is the strand of hair going?) is then combined with the 3D point cloud to create ribbons — local wisps of hair that aren’t connected to anything else. Finally, connection and direction analysis is performed on each ribbon to connect them all up into long wisps that are attached to the scalp.

Most of the magic occurs during this final step, when each local ribbon is attached to create long wisps. Basically, no matter how many photos you take of a real-world hairdo, there’s a lot of occluded (invisible) hair. There’s also a lot of hair that you never see, underneath, adding volume. Imagine a braid, or long hair with ringlets: You might only see an inch of hair before it ducks behind another strand. As far as a computer is concerned, each of these segments is completely separate, and joining them together in some kind of logical way is difficult. In short, this is done through direction analysis, and trying to draw sane connecting lines between ribbons — but for lots more data, see the research paper [PDF].

So far we’ve only shown ringletted hair, but Structure-Aware Hair Capture also works with long sleek hair, short sleek hair, mid-length tousled hair, and what appears to be Einstein’s hair. In all cases, the software creates “hair models that are plausible for animation and simulation.” If you watch the video, it’s clear that the animations aren’t perfect, but presumably it would be fairly easy for a skilled 3D artist to go in and make some tweaks. For an automated process, Structure-Aware Hair Capture is really quite impressive.

Alongside SAHC, a bunch of other awesome technologies will be shown off at Siggraph 2013. For a brief overview, watch the preview trailer below — and stay tuned for further Siggraph coverage on ExtremeTech.

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