Projection Mapping

Throwing computed light back onto the physical surface you scanned

Recap

  • last week you captured a surface as data — this week you send computed light back onto that same kind of surface
  • mapping a projector onto an irregular physical object, not a flat screen
  • calibration: why a straight rectangle projected onto a curved object goes wrong, and how to fix it
  • Studio Brief 1 opens today, asking you to combine this pillar with next week’s programming on-ramp

Setting up the station

Aim a projector at a stand or table where your object can sit still for the rest of the session. Settle the object on that stand before you calibrate, not after — a calibration only holds for one fixed relationship between projector and object.

Keeping the setup fixed

Treat both the object and the projector as fixed from here. A bump to either means calibrating again from scratch.

Calibrating: corners first, then curves

Match the projected image’s corners to the object’s outer edges first — that gets position and scale roughly right. Then adjust for what a flat grid can’t predict: a curved face smears or doubles a straight-on image, an angled face stretches it.

Nudging it into place

Nudge the projection, or reshape the source image, until it sits on the geometry you actually have rather than floating over it.

From calibrated to captured

Map computed imagery onto the calibrated surface and it reads as part of the object, not a rectangle of light sitting on top of it. Capture a still image or clip before you strike the setup — a live projection only exists in the room while it’s running.

What this can build toward: mapping a building facade

The same corners-then-curves calibration, scaled up: a computed light pattern registered to a building’s real windows and ledges, run after dark as a public art piece.

What this can build toward: a mapped performance prop

A mask or prop with a texture mapped onto its own irregular surface so it reads as part of the object under stage lighting, live, in a performance.