How to plan a Motion Capture Shoot – Move Requirements

Once you have written the first draft of your list there are a number of technical and artistic requirements you need to consider about each action before you capture any motion. Review each action and add as much detail as possible to it. Ask yourself ‘if I had to explain to someone how to perform this action, what would I need to tell them?’ You may find this requires extra information from other departments who want the action to conform to specific criteria. Adding the extra detail and involving other departments at this stage will help identify any issues before you commit to motion capture.

The better you understand each action the more information you can provide a motion capture company, the easier it will be to direct performers, the more accurately you can capture your data, the less editing the data is likely to require, the less problems you are likely to encounter and ultimately the easier your project will be and the better your final data will look.

Arriving on the day of your motion capture shoot with a couple of mates and inventing actions as you go along is potentially a very bad and expensive way to go about motion capture.

I have tried to make the following list of consideration as exhaustive as possible so you may find that some points aren’t relevant to your particular project

Start & End Pose – What position does the character need to start and end in? Start and end poses are defined by the preceding and following scenes or actions. It is vital you know what position or pose you character needs to start and end the action in as this can be essential for continuity or if the actions needs to blend continuously with another action.

Distance – How far does the action need to travel? The distance an action needs to travel can be determined by the environment the final action will be used in or by the technical requirements of a game mechanic or crowd engine. Make sure you understand exactly what these requirements are as they will affect the way the action is performed and how it finally appears on screen.

Speed – How fast does the action need to happen? As with distance, speed is usually determined by the same factors. The speed of an action can change the way it is perceived and whether it will work in the context of a shot or a game mechanic. The speed can be recorded as a frame length or second count or as a specific description of the nature of the action.

Motivation – What is the motivation for the action? Understanding why the character is doing the action is one of the most important things to consider. For computer games, where the player is providing the motivation try to consider the context the action is likely to take place in. While ‘finding ones motivation’ can sound quite arty, getting it right can massively improve the realism of the action.

Intensity – What is the intensity level of the action? The same type of action may require different levels of intensity at different times during a sequence of shots or for different levels of a video game. Establish a distinction between what the different levels of intensity involve. Make a note of the intensity level for the action and a brief description of what that level of intensity involves.

Variation – How do similar types of actions vary? If you are planning to capture variations of a particular type of action make sure you know what each variation will look like. Don’t be tempted to write Action_01, Action_02 etc. and hope to invent the variations on the day. It can be difficult to come up with a number of different variations at the best of times without the added pressure of being on a shoot.

Environment – How does the environment affect the action? To ensure the final action integrates with the environment properly it is important to consider everything that will impact on how the action needs to be performed. Make sure you know the dimension of every prop, scenery location and scenery object the performer needs to interact with and any marks they needs hit.

Audio – Does the action require audio cues? Sometime an action may require an audio track to take a cue from. This could be in the form of a foley or dialogue track the action needs to synchronise with. Make a note of any audio you require for the shoot so you can request it from the relevant department ready to take on the shoot.

Duration – How long does the action need to last? There are a number of factors that can determine the length of an action like hardware limitations or technical restrictions. Use a stopwatch to time the duration of the shot or yourself performing the action to make sure it doesn’t exceed any of these restrictions. Knowing the approximate duration of each action will also help when estimating the cost of your mocap data.

Response – How quickly does the action need to happen? Response times are usually determined by how the action will be triggered. Some actions may need to begin instantly while others may need to occur at a specific time so they can be synchronised with a particular event. Understanding this can minimise the need to alter the speed or duration of the action during post work.

Context – How does what’s just happened and what’s going to happen affect the current action? It is important to understand how the preceding and following events affect the current action. The action may need to continue or begin in a particular emotional or physical state to maintain continuity. If the actions creates the impression the character is reacting consistently to what is happening around them it will make the character appear much more believable.

Association – What shot or level does the action belong to? This association can be used to identify how often an action is used and if it is necessary. Understanding where the action is going to be used can help assess if a single action can be used for multiple scenarios. It can also help assess if the amount of work required to implement an action is necessary for the amount of times it will be used.

Props – What props are required to perform the action? Include everything the performer needs to use or interact with when performing the action. It is essential to get the measurements and compare the scale of the prop objects against your performer. Also consider the approximate weight of the prop as this has will have an enormous effect on the way the action is performed.

Scenery – What scenery objects will the performer interact with? If the performer has to interact with the scenery or environment in any way, it is essential to get the measurements and compare them with your performer. The mocap space is essentially an empty box, if the action requires anything other than a flat floor to stand on you will need to include it on the list. Don’t forget to include any safety equipment like mats or harnesses that may also be required.

Performers – How many performers are required for the action? Some actions may need 2 or more performers to interact with each other. Write down the number of performers you think will be needed to perform each action. These numbers can then be used to determine how many performers you will require on your mocap shoot and how much it is likely to add to your budget.