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?
A lot of people think dreams and drugs involve some magical inspiration. I think otherwise.
I rarely get inspired by dreams or drugs, but I have my own secret source of inspiration: mishearing other people. Somebody says something, I misinterpret it, and the misinterpretation is quite interesting – more interesting than anything I would have come up with on my own if asked to generate an interesting idea. Maybe it’s a clever joke or turn of phrase. Maybe it’s a neat idea. Sometimes I misunderstand people’s entire positions, and end up with positions much more interesting than the ones they were trying to push.