Faceted Forms

Every form begins as a circle. Three geometric modifications produce distinct primitive types.

When two same-color circles come within gap range (0.65× minR), a connection is computed. Two types exist, chosen per pair at generation time (~70% rod bar probability).

Fillet Neck Anatomy

Four arcs: two outer arcs (back of each circle) and two concave fillet arcs (the bridge). The fillet circle radius determines neck thickness: Rf = max(Ra×0.55, gap×0.5 + (Ra+Rb)×0.22).

Rod Bar Anatomy

Common external tangent lines touch both circles simultaneously. φ = lineAng ± acos((Rb−Ra)/dist). Contact point = center − R×(cosφ, sinφ). Min bar width enforced at 55% of smaller radius.

Term	Definition
Attract	Force pulling each shape toward canvas center. Controls composition tightness.
Repel	Inter-circle push force within 2× touching distance. Velocity-level separation.
Dampen	Velocity multiplier per frame (0.7–0.98). Lower = more friction.
Same-color attract	Additional pull between circles sharing a color. Creates clusters that form blobs and rods.
Positional correction	6 iterations per frame of direct position pushing. Resolves all circle-circle overlap. Mass-weighted.
KE	Kinetic energy = Σ(v²×mass). Bake stops when KE < 0.12.
Bake	Run physics until rest. Auto-triggers on Generate. Same-color shapes cluster and form connections.

Format	Description
Solid SVG	Flat-fill vector. Per-shape <clipPath> contains fills. Washer holes as <mask> knockouts. Rod bars as polygon fills.
Plotter SVG	Stroke-only for AxiDraw. One Inkscape layer per color. Arc segments clipped by occlusion testing. Rod bars as two tangent stroke lines.
PNG Proof	2× raster with seed/date metadata strip.
Ray SVG	Black background. Shape silhouettes punched as voids. Spiral fills radiate outward from each shape center.

Param	Type	Description
R	px	Circle radius.
cx, cy	px	Circle center.
color	hex	From the Grabie 36-pack marker palette (72 hues).
colorIdx	0|1|2	Which of the 3 active palette slots this shape belongs to.
hasWasher	bool	Punched hole. ~25% of shapes. Shapes with washers skip facet chord cuts.
washerR	px	Washer hole radius. Always < R.
facetDepth	0.28–0.60	Half-angle of chord cut. Deeper = flatter facet.
hasFill	bool	Gets spiral fill in plotter/SVG output.
density	0.5–5.0	Spiral fill spacing. Higher = denser.
mass	0.5–1.8	Physics mass. Heavier shapes move less during Bake.
useBar	bool	Rod bar vs fillet neck. Seeded ~70%. Clusters max 2 bars.
_smoothET	object	Lerped tangent contact positions for smooth rod bar animation (factor 0.18/frame).
_merged	bool	True if part of a blob. Skips solo rendering.