Motion Capture for film or television - Key Concepts 'cheat sheet'

[DMan]

Key Concepts / cheat Sheet
For those of you who would like all the key concepts to be in one easy to read place.....

Breaking scripts down for motion capture, on a t.v. series or feature, is slightly different than for regular film.

You may want to have some shots which are specifically to get particular camera angles

Motion capture shots should be kept to around the three to five minute mark or less.

Longer shots also make it hard for actors re-acting to audio to stay in synch. When actors react to prerecorded audio keep it to 1 min or less.

Break down the script into groupings by type

Sort this breakdown by volume size

All markers and bones must have unique names.

The skeletal hierarchy preferred by MotionBuilder should be used if it will be used to solve the motion.

All actors must have unique markers which identify them from everyone else, but must use the same number of markers.

Create an ‘actor code’ for each actor that is added to each shot name that the actor is in.

Create a ‘key’ that indicates marker set and actor codes for all actors captured.

Props should be identified the same way in every shot.

Compose a move list w/ appropriate information

It may be preferable to shoot all types of motion which may occur on a particular set, when that set is ready for capture

Shoot motion in the appropriate capture volumes only.

Do not mix upper and lower case in filenames

If you expect people to react to audio playback during capture, you MUST audition them this way or you will have problems.

If you choose to have actors react to audio it will mean less work in the end, but is harder on the actors.

you record dialogue during body capture, you will get better acting

When re-acting to audio files, the files should be as complete as possible

For film or series work, cast stand-ins for every role.

Once you have completed motion capture casting, have suits created specially for each of the talent that will be acting.

Only use mocap suits from 3x3design if possible.

Special Care should be taken when using stunt rigs and doing wire work

If anything happens to a stunt person’s gear, it should be reported to the stunt person, no matter how small.

Stunt harnesses move during capture. Try not to place markers on them whenever possible. get a tpose at the start and end of the stunt.

Take special care with the markers, which may be effected by the stunt gear

Animals may be required to wear mocap suits, if being captured (they will need time to adjust to wearing it)

Pickup shoots should be planned when the schedule is initially created – BEFORE any capture has been completed.

A Mocap animatic should be created.

The move list and database fields needed for capture should include appropriate mocap info (see list)

It can be very detrimental to shoot motion capture on an uneven floor surface if you dont have a way to remap the feet onto the cg terrain

Make sure that the floor of the studio is appropriate for capture and for actor comfort.

Permanently tape the floor out in a measured grid.

It is important to shoot motion capture in a suitable studio environment.

Have multiple reference cameras on set that you can trigger simultaneously and remotely.

You should have a device that creates a flash of light and makes a sound, whenever the system is triggered (if you record audio or video) as this can aid in synchronizing things in post

It can be beneficial to the actor to have the display projected out of Filmbox and onto a wall in the studio that is easily viewable.

You may want to capture the movements of a cameraman who is viewing the playback of some virtual scene, long after capture is over, or you can capture them along with primary action

A good motion capture studio will usually have a green room close to set,

Sets and Props should be kept as basic, modular, and non-occlusive as possible

Complex  (non-flat) CG set floors should be roughly poly modeled until after the final capture

Only the surfaces the actors touch need to be built on set. Everything else is just eyeline indicators.

Try and use a rig whenever possible. Try not to  use tripods unless it is cannot be avoided

Create job descriptions for the people who might be needed on set(see list)

Optimize cameras – camera placement. field of view, focus, and overlapping coverage are critical !

The Volume you create must be robust enough to capture the kinds of motion that is required.

The studio must be have equipment on hand which will make placing and accessing the cameras possible

Motion Capture Cables are fragile. People who will handle them must learn how to wrap cable before they begin to work with the cabling.

Important issues for mocap skeletons are joint axis orientation, joint positions, bone lengths and naming.

Mocap friendly, standardized skeletons should be used in all characters that will have motion capture applied to them.

Make sure skeletons meet all naming and construction requirements for your solving package, as well as your pipeline

Characters should be modeled with their palms down, thumbs out, clavicles slightly raised up in the Tpose

 Markers can either be made in-house or purchased from several sources.

Marker set should be redundant enough to accommodate any loss of markers, without it being a lost shot.

 Realtime may require marker sets that Offline capture does not.

Make sure you have a good idea of what you will do, LONG before you arrive on set.

Shoot motion in an easiest to hardest order.

Have enough storage space & a good backup scheme in place with lots of redundancy.

Make sure to schedule enough time for face capture – it can take as long as ALL of body capture - if done separately!

Facial Capture requires a minimum of 6 cameras

CG heads which will be animated with motion capture should be modeled with the mouth open in a relaxed pose



 If you do use a service bureau, make sure you know if the service bureau is dedicating all their resources to your project or not.

A mocap heavy feature film can expect to pay between 800,00 – 3,000,000 dollars for one movie’s worth of motion capture, if a service bureau is used.

Motion capture for video games can cost $125,000 and up, for each game, depending on amount and types of motion which will be captured, if a service bureau is used.