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 couple of months back, Craig mentioned in a video that he has a doc filled to the brim with snippets of text—nice words, compliments, and thanks that had been sent his way for his work. Whenever someone says something nice he just copy/pastes it into that doc.
It sounds silly at first and perhaps a little egotistical. Behold! I have a document that proves how great I am!
But I started doing it just to see what it feels like and…hey…actually? It’s so great! When I’m feeling low (often) or whenever the world feels unstable (extremely often) it’s so very nice to return to a few kind words about my work. It reminds me just how much these words of praise mean, it reminds me that I ought to pass that favor along.