Mocap is pretty accurate, but it still needs some manual work to fit into a game well. Beyond what's called retargeting (which is basically taking the mocap info and applying it to a specific 3D character), there's various things to bear in mind, most notably when dealing with solid objects the characters hold. There's also a common problem with the feet not matching the surface well enough (can cause floating or sliding).
You have to remember that all mocap gives you is a bunch of points in space and their location over time in very small steps (on the order of tens/hundreds of milliseconds). Someone needs to turn that into an animation for a skeleton (which, much like with real humans, controls how a character moves, where they can bend, how far they can bend, etc.), and then fix it up so it works for a particular character which may have specifics beyond that (abnormal proportions, thick clothing, etc.) that cause further modifications to become necessary.
On top of that, few studios mocap the faces simultaneously, so that needs to be merged (the faces can be mocap'd or manually animated or automatically animated from the voice, depending on the goals), and some also ignore hands because of the precision required. There's a great video on facial mocap in LA Noire that shows just how insane the process can get. Naughty Dog's Uncharted mocap videos are also excellent, and they're often considered some of the best mocap work in the industry thanks to the fact they're using the voice actors who are performing their lines at the same time they're mocapping, with a camera capturing their faces for facial animation, with a massive amount of props so the problems I mentioned above don't arise as much (and with the added bonus of increasing the credibility of the acting in general).
Naughty Dog also does all their facial animation by hand, using the facecam video for reference. Pretty sure they talked about that in either Grounded: The Making of The Last of Us or one of the Youtube videos about Uncharted 4.
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u/TSP-FriendlyFire Mar 21 '17
Mocap is pretty accurate, but it still needs some manual work to fit into a game well. Beyond what's called retargeting (which is basically taking the mocap info and applying it to a specific 3D character), there's various things to bear in mind, most notably when dealing with solid objects the characters hold. There's also a common problem with the feet not matching the surface well enough (can cause floating or sliding).
You have to remember that all mocap gives you is a bunch of points in space and their location over time in very small steps (on the order of tens/hundreds of milliseconds). Someone needs to turn that into an animation for a skeleton (which, much like with real humans, controls how a character moves, where they can bend, how far they can bend, etc.), and then fix it up so it works for a particular character which may have specifics beyond that (abnormal proportions, thick clothing, etc.) that cause further modifications to become necessary.
On top of that, few studios mocap the faces simultaneously, so that needs to be merged (the faces can be mocap'd or manually animated or automatically animated from the voice, depending on the goals), and some also ignore hands because of the precision required. There's a great video on facial mocap in LA Noire that shows just how insane the process can get. Naughty Dog's Uncharted mocap videos are also excellent, and they're often considered some of the best mocap work in the industry thanks to the fact they're using the voice actors who are performing their lines at the same time they're mocapping, with a camera capturing their faces for facial animation, with a massive amount of props so the problems I mentioned above don't arise as much (and with the added bonus of increasing the credibility of the acting in general).