caustics
Caustic (optics)
Caustics made by the surface of water.
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.
Hiding Images in Plain Sight
An Article by Matt FerraroI recently made a physical object that defies all intuition. It's a square of acrylic, smooth on both sides, totally transparent. A tiny window.
But it has the magic property that if you shine a flashlight on it, it forms an image.
Caustic Engineering
An Article by Geoff ManaughA 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.
Architectural Caustics
A Research PaperTo 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?
Why Sketch?
What you have observed closely
Drawing requires that you pay attention to every detail—even the seemingly unimportant ones. In creating an image (no matter how skillfully), the lines and tones on the paper provide ongoing feedback as to what you have observed closely and what you have not.
A single image
Scientific illustrations can achieve certain things that photographs cannot. A good illustration can portray difficult-to-photograph or rarely witnessed events. It can incorporate everything that’s important into one single image or show a special view of a subject.
It would be next to impossible to observe, in nature, a dozen different aquatic species in their natural habitat, posing perfectly together and all in focus at one time—but such a scene can easily come to life in an illustration.
Parallel refinement
My studies of live animals usually begin with a series of quick drawings, all on a single page. When the subject changes position—which it pretty much always does—I abandon the first sketch and start a new one. Continuing on in this way, the page fills with mostly unfinished squiggles until the animal eventually resumes one of its earlier poses. If that happens, I add as much detail or refinement to one of the easier sketches as I can. While this is all going on, I also jot down written notes that help explain what I observed and what seemed significant.
Color reproduction
In-person, live observation of color is a practice for which I feel there is no adequate substitute. Photographs are often imprecise in reproducing color.
The negative spaces
Focus on the negative spaces surrounding the object to give yourself a fresh perspective on the form.
Hues subdued
Colors in nature are, in general, more subdued than what comes directly from the pencil or the tube of paint. Greens, especially, tend to be a lot browner than we expect.
Unfinished
Leave the drawing unfinished. Record as much information as you need, but don’t draw any forms, details, or colors that are merely repetitive. The back and front of a representative flower on a plant, for example, or half of a bilaterally symmetrical animal may be all that’s necessary.
A red sea fan
Ink and watercolor drawing of a red sea fan.
Sketches
Sketches and written notes.