Features

Exorcising Satan's Rotoscope: Motion Capture from an Animator's Perspective

Motion capture. Perhaps no single technology frightens animators more. Whether it's the technical hurdles or the perception that it will put them out of a job, many animators have a fear and loathing of motion capture. The truth is animators have nothing to fear from mocap, except avoiding it. That will definitely lead to putting you out of a job. My prediction is that within the coming generation of video games, nearly every title will involve at least a modicum of captured motion. Animators will need to learn to, if not embrace motion capture, to co-exist with it.

We are entering into a new generation of gaming. Rather than dealing with a blocky low-polygon guy jerking by at 12 frames a second, we have highly detailed character running around at a blazing 60 frames a second. Simple cycles baked out at 15 frames a second won't really do the job anymore. Animators must find a way to fulfill the desire of gamers to see motion as realistic as the character models being animated while satisfying the budget requirements of the project.

What Motion Capture Can Do

Motion capture does one thing and does it extremely well -- and that is take the movements of a performer and put them in the computer. That's it. You can capture pretty much anything you are able to stick the markers to. Whether that's Kobe Bryant, a horse or even you doesn't really matter to the computer. It's just a bunch of dots moving through space.

So why is it any good at all? To be slightly redundant, it does reproduce that motion quite well. Whether it's the distinctive footwork of a NBA all-star or the subtle shifts in weight and movement of woman standing around seemingly doing nothing, realistic motion can be deceptively complex. An animator can convince you something is alive. A truly skilled animator can even reproduce many of the subtleties of real movement.

But at what cost? Why have your best animator (or in many smaller studios cases, only animator) spend a week animating all the subtleties of a motion that would take 20 seconds to record on a stage? That is a tremendous waste of time, talent, and money. It also isn't much fun to the animator. Most animators would rather spend their time animating the death of that nine tentacle slime beast than another $&*#! walk cycle.

What Motion Capture Can Not Do

This is not to say that motion capture is ideal for every animation need, even for realistic animation. If your title calls for cartoony animation, motion capture is not your best option. And even if you need realistic motion, there is a good chance your game will need some elements that cannot be captured. Be it swimming, suffering a serious injury, or an imaginary creature.

Motion capture is not a plug and play technique. You will need to workaround it's shortcomings to effectively put the technology to use.

Capturing the Motion

Know what you don't know.
This is by far the best advice I can give on getting good motion capture from your vendor. There are a lot of technical issues with motion capture. Don't try to help with them. Let the people who do this day in day out take care of it. Ask questions, but defer to them on technical issues. It's hard, but it'll lead to better captures. Make sure you get the end result you're after, but the in between issues are best left to them.

Be prepared. (Apologies to the Boy Scouts)
Know exactly what you need, prop wise, set wise, etc. That way they can have everything on hand and ready.

Realize you are, in fact, dealing with a real live human performer.
Hopefully you were on hand for the talent auditions. This will definitely help on the first day of the shoot, as you will at least have some knowledge of each other's personalities. Your performer is neither a performing monkey nor robot. They will get tired, they will get annoyed and frustrated at doing the same thing over and over and over, and they may not understand exactly what you want. Keep this in mind as you work with them. After your first day, realize how tired you are at 6:00, and then realize you just sat around. They jumped through hoops all day (maybe literally). Make your shooting schedule conform to the realities of working with a person. Don't put your most physically demanding shots first or last. Give your guy time to warm up, but not get too tired. Keep their health in mind. If you see them rubbing their shoulder or ankle, give them a 15-minute break. Keep in mind these guys are (usually) trained professionals. They know how to hit a mark and do the same action with remarkable precision over and over again. Use their knowledge and expertise to your advantage. You may not know how to use a missile launcher, bastard sword or do a triple back handspring. They might.

Stay in control.
You are spending a good bit of money on this. You should expect to get what you want. While you should always follow the Golden Rule and #3, make sure you leave happy and with everything you need. Make sure you check the actual capture data on the system. Most modern systems provide near instantaneous replay of the motion. Even if the performance was perfect, a loose marker can mess up the final data.

Scheduling is everything.
Schedule an extra half-day of stage time to get everything you need, anything you forgot (you can USUALLY add extra shots) or give some breathing room for any delays. After all, if that time goes unused, that's still cheaper than if you have to come back for re-shoots later.

That's the basics of a good mocap shoot. A lot of it is obvious, but it's usually obvious AFTER the fact.

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Mapping Motion Capture

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