This project is based off of John Douglas Power's "Haliades" (ha-LAI-ah-dees), a kinetic sculpture consisting of wooden bars, steel supports, and an electric motor running the motion. The concept is based off of sirens from greek mythology, where the visual is hypnotic but the sound produced by the sculpture is menacing.


There were several ways in which I approached imitating this mechanism.

The first attempt used two animated sine curves to drive the movement of the bars, as seen as an invisible line on the edges of the sculpture. Using a point wrangle, the points on a line are animated using sine in the Y and Z, with the second curve line offset by PI and translated a distance away.

@P.y = sin(@ptnum * 0.25 + @Frame*0.08 + 3.14) * 0.5;
@P.z = cos(@ptnum * 0.25 + @Frame*0.08 + 3.14) * 0.5;

An add node was used to create lines between the curve points, and a box was swept across the lines to create the wooden bars. The problem with this method was the texture could not be properly projected onto each individual wooden bar, as all the bars are seen as one primitive. The result is "swimming" textures. 

The second attempt solved the issue with the "swimming" texture. As the sweep node was the root cause of the texture problem, the solution was then to use actual geometry copied to the lines. Still using the point wrangle sine curves, another point wrangle was used to calculate the dot product between the curve and the z-axis. The copystamp-ed geometry referenced the rotation angle of the dot product. The result was the geometry could be UV-ed before being copied, so the texture stayed static. 


The problem with the first two methods was the movement was not true to the motion, as the sculpture has a point at which the bars are always in contact with a support bar underneath.


The final attempt referenced the curve movement and the static contact point, so the second curve is left as a straight line and translated to the point of constraint. The geometry was then scaled past the point of constraint to imitate the sine movement while always staying in contact with the point.

To create a second group of wooden bars, the sine curve was copied, and the copied line was translated in the negative, followed by the same procedure above so that the animation matched perfectly. Mirroring the entire sculpture instead of copying the curves proved to be inaccurate as the points did not line up exactly for some reason. The steel supports used the same process with the sine curve and static line.

Look Development

The lighting is based on museum lighting, where all the lights are focused on the object. The scene has four spot lights in a large empty room. Other attempts played with using windows with light portals to imitate natural light coming into the room, however I found the windows themselves were too bright, taking the attention off the actual sculpture. Another version used fluorescent lighting with mirror walls to imitate the look of infinite waves, based another work of John Douglas Powers, "Lethe".

March 12 2018

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