- Accurate/High Resolution
Fast and Accurate: ScannerKiller offers an amazing package that can do a very high resolution full body 3D scan in an instant. It may even be possible to capture video at the speeds they're doing. They use a method called Stereo Photogrammetry and pre-calibrating their cameras. Despite the precalibration the setup still need lots of cameras (16 by my count) and projecting a randomized texture on the subject with a flash to add texture to smooth objects, some of which may be applied to a DIY option. But if you're going to buy one from them the asking price is $17000. There's also NextEngine, endorsed by Jay Leno. $3000. And really it's not that fast.
Fast and Cheap: ReconstructMe and a Microsoft Kinect and you're good to go. Sure the result looks like it's covered in mud, but it only took a second and only cost you about $100 for the Kinect.
Accurate and Cheap: There are lots of options in this category. 123DCatch or Agisoft StereoScan use photogrammetry but can be tricky. For 123DCatch like apps you need a lot of photos to make it work (more than ScannerKiller). Plus if your camera isn't super accurate or if the lighting changes it could mess up the whole process. 123DCatch is free and works by uploading your pictures to their server where they process it, Agisoft has a similar app for $179 but you download it and processes on your computer. You could also download a free copy of the David Scanner software with a decently high resolution webcam and either a laser line level or projector. David Scanner has a great tool chain to stitch multiple models together accurately. But with all these options the subject being scanned needs to hold very still through the scanning process which can take minutes to complete. Not good if you're trying to capture a child for posterity. There are some other DIY options as well but their tool chains are less complete.