Spiral Drawing

Like a toy from our youth, the Spiral Drawing generator draws curves based on a “pen” that’s locked to a point on a gear (a rotor) that rolls within—or without—a larger ring (a stator). While the pattern draws, the ring remains in a fixed location, and the gear rolls along the inner edge or outer edge of the ring.

Adjust this generator using the controls in the Generator Inspector:

• Auto Draw: A checkbox that, when selected, creates an animated drawing. When Auto Draw is deselected, the drawing is static.

• Auto Draw Style: A pop-up menu that sets the style of the drawing instrument. There are two choices:

  • Pen: Draws solid, even lines in the Canvas in a pattern defined by the generator controls.

  • Laser: Simulates a laser in the Canvas in a pattern defined by the generator controls.

• Draw Speed: A slider that adjusts how quickly the drawing is created.

• Cycle Start: A slider that sets the beginning location of the drawing.

• Center: A slider that sets the center of the generator pattern.

• Pen Color: Color controls that set the color of the drawing.

• Pen Width: A slider that defines the thickness of the drawn lines (Pen or Laser).

• Pen Blend Mode: A pop-up menu that sets the blend mode of the generator to Normal or Add.

  This setting is a separate from the blend mode of the group. Setting the Pen Blend Mode to Add results in an additive effect (it’s added to the blend mode of the group).

• Pen Location: A slider that sets the position of the pen within the drawing gear. (You can also use the Adjust Item tool to modify this parameter with onscreen controls. For more information, see Modify or animate a generator.)

• Line Smoothness: A slider that defines how uniform the lines are. Lower the value to create more crimped, linear lines.

• Ring Radius: A slider that controls the size of the drawing. When Inside Ring is chosen from the Gear location pop-up menu, all drawing occurs inside the radius of the ring. When Outside Ring is chosen from the Gear location pop-up menu, all drawing occurs outside the radius of the ring. (You can also use the Adjust Item tool to modify this parameter with onscreen controls.)

• Ring Teeth: A slider that controls the number of teeth on the outer drawing ring.

• Gear Teeth: A slider that controls the number of teeth on the inner gear. A lower Gear Teeth value results in a more complex drawing. (You can also use the Adjust Item tool to modify this parameter with onscreen controls.)

• Gear Location: A pop-up menu that sets whether the drawing occurs outside or inside the ring. There are two choices:

  • Inside Ring: All drawing occurs within the radius of the ring.

  • Outside Ring: All drawing occurs outside the radius of the ring.

• Ring Rotation: A dial that turns the ring (and the attached gear).

• Gear Rotation: A dial that turns the gear (and the attached pen point).