Phase

Phase is the single most useful abstraction in this medium. Understand it and a large family of effects becomes one idea with different settings.

Phase is "how far around the figure you are"

Every generated figure is driven by a value that ramps smoothly from 0 to 1, over and over. Feed that value into the shape's equations and it returns a position. One complete 0-to-1 ramp is one complete lap of the drawing.

Think of it as a percentage:

• 0.0 — the start of the figure
• 0.25 — a quarter of the way round
• 0.5 — halfway
• 1.0 — back to the start, and the ramp resets

The rate of that ramp is the drawing frequency. The shape of the ramp is where the technique lives.

Why this matters: phase effects are shape-independent

This is the payoff, and it is worth stating on its own:

Anything you do to the phase works on every figure, because it never touches the geometry. It only changes when the beam is at each point.

A circle, an imported logo, a 3D wireframe, a piece of text — a phase effect treats them identically. You do not need a special version of the effect per shape, and the effect cannot break the drawing, because the drawing is the same set of points either way.

Trace — draw only part of the figure

Scale the phase by a factor below 1 and the beam only covers part of its lap.

• Factor 0.5 draws half the figure.
• Factor 0.25 draws a quarter.
• Add an offset to choose which part.
• Sweep the offset and the visible arc travels around the shape.
• A factor above 1 draws more than one lap, retracing.
• A negative factor draws the figure backwards, which looks identical and sounds different.

Trace is how a figure gets revealed, wiped, or animated without any change to the artwork.

Note what happens at the ends: because the beam cannot stop, a partial trace still has to return to its start. You get a bright arc where the beam works and a faint line where it races home. That faint return line is not a defect — it is the same effect described in Brightness, and it is often the most useful thing on screen.

Dash — break the line up

Multiply the phase by a whole number, take the whole-number part, and divide back down. Instead of a smooth ramp you get a staircase, and instead of a continuous line you get evenly spaced dots — one per step.

Add a second, synchronised ramp that runs 0 to 1 within each step, and the dots stretch into dashes. Scale that inner ramp to control dash length: short for a dotted line, long for a nearly solid one.

Dashes are the closest a two-channel signal gets to a broken line. They are not true gaps — the beam still travels between them — but at speed the travel is faint enough to read as a gap. To get real gaps you need a blanking channel, which is the subject of Multiple objects.

Offset — move the starting point

The simplest operator and an easy one to underrate. Adding a constant to the phase rotates where the figure begins, without moving the figure.

On its own that is invisible on a closed shape. Combined with anything else it is essential: it aims a trace, positions a dash pattern, and places a brightness hotspot. Most phase effects need an offset to be useful, which is why the controls that expose them almost always come in pairs.

Order matters, and that is a feature

Phase operators compose, and they do not commute:

• Trace, then dash — you take a quarter of the figure and then break that quarter into dashes. The dashes are confined to the visible arc.
• Dash, then trace — you break the whole figure into dashes and then reveal a quarter of the result. You see a quarter of a dashed figure, and the dash spacing is set by the whole shape.

Same two operators, same settings, different image and different sound. When a chain has an explicit order, treat that ordering as a control rather than a technicality.

The controls

The phase chain is in the Shape Morph panel, below the dwell controls.

All of them are MIDI- and OSC-learnable, and all of them default to off, so the chain costs nothing until you touch it.

Try the order switch with Trace around 50% and Dash around 4. With trace first you get a half-figure broken into four dashes. With dash first you get four dashes spaced around the whole figure, of which you see half — so the dashes look further apart and there are fewer of them on screen. The panel greys the switch out with "no effect yet" when only one of the two operators is on, because in that case the orders genuinely are identical and a control that pretends otherwise is worse than none.

A note on what dashes do to brightness. Each dash covers less of the figure than its step, but takes the same time, so the beam moves slower along a dash and faster in the gap. Dashes come out brighter than the line they were cut from, and the gaps are faint rather than empty. That is the same speed-is-brightness relationship as Brightness, arriving whether or not you asked for it.

Rate is also a phase operator

The other thing you can do to a phase ramp is change its speed as it goes — run fast through part of the lap and slow through another. Because dwell time is brightness, that is a brightness control; because it changes the waveform, it is also a timbre control.

It is the same family of maths as everything on this page, but it earns its own treatment. See Brightness.

Related

• Brightness — phase rate, the fourth operator
• Multiple objects — cutting the phase into slices, the most powerful thing you can do to it
• Shape tools — the generators these apply to