Glossary of Technical Theatre Terms

Automation – Scenic


AUTOMATION
1) Facility available on larger sound mixing desks allowing channel muting or even fader moves to be taken under the control of a computer to ensure accurate and repeatable mixing.
2) Describes the method used instead of stage crew for moving bits of set around shows with a big budget. See MOUSE, SPADE.

AXIS
(plural AXES). An individually controllable moving element controlled by a scenic automation or powered flying system. For example, a system controlling three flying pieces will have three axes of automation.

BRIDGE LIFT
An elevator which raises and lowers sections of the stage floor, usually by electrical or hydraulic means.

CONTINGENCY
An alternative plan of action if a piece of technology fails to operate. Large-scale productions have to continue wherever possible to avoid having to give the audience refunds. So if a small piece of the set fails to work or gets stuck (particularly automated scenery) the cast and crew will have rehearsed an alternative choreography to work around it while the crew repair it. For example in The Lord of the Rings The Musical in London, when the revolving stage with multiple lifts had a safety sensor triggered, the automation went into 'E-Stop' mode, a thunderclap sound effect was triggered, the stage lifts went to a flat floor (once it had been found safe to do so) and the actors for the next scene were rushed into new positions, while the actors on stage immediately adopted a new choreography.
It's vital that contingencies are worked out in advance so that as soon as something goes wrong, the show can continue, and the audience will hopefully be unaware.

DEAD MAN'S CONTROL
Also known as DEADMAN'S BUTTON (DMB). This is a handle that has to be squeezed by a technician in order for a pre-programmed automation sequence to take place. If for any reason the relevant technician is not in position, the system does not allow the sequence to run.

EMERGENCY STOP
Also known as E-STOP, all scenic automation or powered flying systems have an emergency stop facility built into them. The pressing of any e-stop button in the system will immediately halt any movement and prevent any further movement until the system is reset.

FEEDBACK
(Automation) Process by which information about the position of a piece of scenery is fed back into an automation system to ensure it's running correctly.

HYDRAULIC
A system of controlling machinery or moving scenery using oil or water under pressure to move a piston or 'ram'. Used in many large-scale shows to automate scene changes.

IMPRESSARIO
1) Now more likely to be called a Producer, the Impresario organised and financed the performing arts. Term originated in the Italian opera, in the mid 18th Century.
2) Automation control console and system by AVW Controls in London, UK.
AVW Controls website

LIMIT SWITCH
Part of a scenic automation or powered flying system - a switch positioned to send a signal to the controller when it's reached the end of it's travel.

MCC
(Automation) Motor Control Cabinet / Centre. The equipment containing the drivers and controller hardware for automation motors.

MOUSE
Moving part of a scenic automation system. Mice run on cables under the stage floor, and can be made useful by inserting a metal SPADE through a wheeled piece of scenery into the mouse, which then pushes or pulls the scenery with it. The scenery sometimes has additional guide pins which move in guide tracks which allow the scenic piece to move in more complex directions.

PERFORMER FLYING
A manual or electrically driven system for lifting performers off the stage and allowing spectacular stunts and aerial sequences to be performed.

REVOLVE
A turntable built into the stage floor on which scenery can be set and then driven into view. Can be electrically chain driven either as part of an automation system or via simple start/stop controls, or manually rotated. A revolve can also be built on top of an existing stage.
A partial revolve with a stationary centre section is known as a DOUGHNUT REVOLVE.
See also WAGON STAGE, JACKKNIFE STAGE.

SAFETY EDGE
A safety sensor on the edge of a piece of automated scenery (usually a moving platform) that the automation system uses to detect something or someone out of place and take appropriate action.

SHOW DECK
A false floor built on top of the theatre stage, which contains technical elements such as automation tracks or revolves, concealed lighting or smoke effects. In some large shows, the show deck completely replaces the existing theatre stage, which is put back into position when the show has finished it's run.

SPADE
Thick metal blade which is inserted through a piece of moving scenery into a MOUSE to allow the movement of the scenery to be controlled by an AUTOMATION system.

SPADING UP / SPADED UP
The act of preparing an item of scenery to be moved by a scenic automation system using a MOUSE / SPADE system.

SUNROOF
(US) Mechanised cover for a scenic automation trapdoor - also known as a Drop & Slide Door.

TRUCK
1) Wheeled platform on which a scene or part of a scene is built to facilitate scene changing. (e.g. "This scene happens on the balcony truck")
2) (TV/film - verb) To move a wheeled camera sideways.

WAGON
(also known as TRUCK). A large wheeled platform which can be moved around the stage either manually by crew or by a scenic automation system. See also WAGON STAGE.