In theatre, a platform (also referred to as a riser or rostrum) is a stationary, standard flat walking surface for actors to perform on.
This is in contrast to scenery wagons, which are mobile platforms that are supported by casters instead of feet.
Occasionally, a layer of muslin is added on top of these materials, as it takes paint better than other options.
Framing is most commonly made of nominally 2"x4" lumber or rectangular steel tubing, oriented so that its longer dimension is vertical, perpendicular to the lid.
The legs or stud walls that support the platform typically require diagonal cross bracing, often made of very thin lumber.