I mentioned to Toby and Matthias that splines were originally physical tools/techniques (it’s hard to separate the two, sometimes):

To draw curves, especially for shipbuilding, draftsmen often used long, thin, flexible strips of wood, plastic, or metal called splines (or laths, not to be confused with lathes). The splines were held in place with lead weights (called ducks because of their duck-like shape). The elasticity of the spline material combined with the constraint of the control points, or knots, would cause the strip to take the shape that minimized the energy required for bending it between the fixed points, this being the smoothest possible shape.

Wikipedia suggests a direct causal link between physical and virtual splines:

In 1946, mathematicians started studying the spline shape and derived the piecewise polynomial formula known as the spline curve, or spline function. This has led to the widespread use of such functions in computer-aided design, especially in the surface designs of vehicles.

I’m struggling to find photographs of the splines in action. This yacht-drafting forum is close, but not quite the image I was looking for:

<Spline+Weights.jpg>

What’s the word for inverted skeuomorphism?

Your correspondent,

R.M.O.

On Oct 9, 2015, at 4:30 PM, Dave Cerf wrote:

This is very beautiful. Bezier curves consistently frustrate me: in pure code I find them nearly impossible. In drawing apps they are tolerable but I get very confused when drawing shapes what the best approach. I like the direct manipulation approach shown here.

I don’t know much behind the math of bezier curves, but I’ve always wondered if there is a way to apply what one “knows” in their body intuitively, about physics, to curve drawing: tension and looseness, for example. I’m thinking, for example, about Gaudi’s experiments with curves using simple gravity. To me, it seems much easier to let physics do the work than to draw this with Bezier curves.

<sagrada2.jpg>

On Oct 8, 2015, at 2:34 PM, Matthias Graf wrote:

Toby and I are currently experimenting with tangibles on the lunch table.

I wanted to document the first little prototype:

<2015-10-08-142640.jpg>

The 4 markers (reacTIVision fiducials) can be dragged to draw a cubic bezier curve. Video attached.
Or try it out yourself as long as it is still hot. :)

-Matthias

<TableBezier.webm>