Active marker

A tracking reference that emits light or radio waves, often a strobing LED

Camera tracking

The solving of a live action camera’s position and orientation. In a real-time scenario, these coordinates are sent to the engine enabling the equivalent virtual camera to move identically. There are a variety of tracking methods such as mocap markers, a SLAM tracking device on the camera, or encoding the...

Degrees of freedom (DoF)

The number of dimensions an object or headset can move or be tracked in 3D space. A 3 DoF system can track position or orientation, but not both simultaneously, while a 6 DoF system can track position and orientation simultaneously.

Depth compositing

The use of machine vision or other techniques to derive a depth matte which can then be used to accurately occlude cg and live elements for simulcam or other visualization purposes. Can be advantageous when compared to earlier chromakey type compositing techniques.

Inside-out tracking

A method of camera tracking which uses a sensor mounted directly on the camera and searches for trackable features such as markers in the ceiling or a map of the physical set using machine vision techniques. See also outside-in tracking.


The delay from when a signal is sent to when it is received/displayed at its destination. Reducing signal latency is a key guideline for success when using virtual production techniques. Modest latency can be managed with prediction, interpolation and overscan.

Lens mapping

Calculating the distortion of a lens by shooting a grid. Used in making rendered CG elements distort the same way as the lens on the live action camera. See also camera calibration and alignment.


A physical reference for tracking purposes. See also active marker and passive marker.

Motion control (Moco)

A special rig which uses mechanical servos and computer control to create precise, repeatable movements for visual effects shots. Can be applied to camera rigs or to physical elements.

Outside-in tracking

A method of camera tracking which uses cameras or sensors mounted on the perimeter of a volume to analyze the position of the camera and other objects. See also inside-out tracking.

Passive marker

A tracking reference object that reflects light, often a sphere covered in retro-reflective material or a printed design for image based tracking

Simultaneous localization and mapping (SLAM)

A method of tracking which analyzes physical features of the real-world to compute position and translation in real-time.


Nickname for the tracking object affixed to a motion picture camera for outside-in tracking. Also referred to as the ‘crown’ or ‘tiara’. See “Outside-in tracking”


The process of determining the position and orientation of a camera or other object relative to the scene via various optical/digital methods; used for integration between the virtual and physical worlds.


A mechanical input device with encoders attached so that any motion of the device can be read by a computer as locations or rotations in 3D space. Waldos are used to assist in the animation of motion-controlled rigs for virtual environments and to puppet virtual characters.

Witness camera

Camera(s) placed on set to provide alternate perspectives on a shoot and provide a comprehensive understanding of the action within a scene. Often used to facilitate remote collaboration, or to capture additional data for later visual effects work.