In certain conditions, the white walls at home take on the character of a light box. In traditional Japanese architecture the intensity of atmosphere has a lot to do with the way natural light is filtered through the shoji paper panels, suffusing the interior spaces with subdued light, calming the spirit and sharpening the senses.
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?
Ebenezer Howard set spinning powerful and city-destroying ideas: He conceived that the way to deal with the city’s functions was to sort and sift out of the whole certain simple uses, and to arrange each of these in relative self-containment.
And he conceived of good planning as a series of static acts; in each case the plan must anticipate all that is needed and be protected, after it is built, against any but the most minor subsequent changes.