In optics, a caustic is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface. The caustic is a curve or surface to which each of the light rays is tangent, defining a boundary of an envelope of rays as a curve of concentrated light.
A piece of milled plexiglass acting as a projecting lens; via the Computer Graphics and Geometry Lab at the École Polytechnique Fédérale de Lausanne
New milling techniques applied to glass and plexiglass panels could be used to “create windows that are also cryptic projectors, summoning ghostly images from sunlight.”
[Pauly and Bompas] hope that the technique will be used in architectural design, to create windows that mould sunlight and throw images or patterns onto walls or floors,” which, if timed, milled, and manipulated just right, could produce a slowly animated sequence of images being projected by an otherwise empty window during different times of day.
To control the shape of a caustic pattern generated by a specular or refractive surface, we need to solve the inverse problem: how can we change the surface geometry, such that incident light is redirected to produce a desired caustic image?
Prescriptive feedback limits creative collaboration. I’ve seen it time and time again, but I’ve struggled to articulate the exact reasons and their remedies. Recently, though, I got some insight from an unusual source: a game of chess.
In hand and brain chess, each team has two players: a “brain” and a “hand.” At the beginning of each turn, the “brain” tells the “hand” which piece to move, and the “hand” then has to move that piece, but can move it wherever they think it should go. No other communication is allowed.
In every feedback conversation, one person is the hand. That’s the person doing the design — they’ll leave the meeting and go back to their computer and fire up a dozen Adobe apps. The other people in the room (virtual or otherwise) are the brain. Regardless of their skill in design, it’s their job to give the hand some constraints to work within.