One zone node at the massive roots' centre of mass owns the only global term (SubzoneReach is the one place the subzone shape is decided: isolated-subzones). WellNode gains Extent and Anchor; a belt orbit's extent is its outermost asteroid. GravityField.SeriesFrom = 0.4 is emitted into the shader template and Gravity.cginc. Tests: the spec's WellLawTests; the old seam test is replaced by TheBandPotentialIsExactInSinglePrecision. GravityFieldParityVerify runs the multi-root fixture (second sun, moon inside the planet's Roche limit, far window): PASS, largest drawn tau 1.228, max error 0.01028 u. The dotnet suite has not been run at this commit.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
GravityField is now the band term U(eps, inner, outer) (C4 smoothstep fade, closed form and a series for tau > 1).
WellTree is built once per Zone from the orbit tree: node terms, reach, support, the pruned Force/Potential walk and
PullAround (rails). Zone.GetHeight/GetForce/PeriodAround delegate to it; WellReference, _wellOn, _strengths,
Strength() and DrawAhead.Well are gone; GravityLowering and the shader template take the flat term list;
HeightExaggeration halves to 2.0491803.
Does not pass yet: Gravity.cginc is not regenerated and PotentialOwnerTests/OrbitsFromFieldTests still spell the old law.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
