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Part of the world-building-3d skill. The skill links here when your agent needs the detail.
Load this reference before using Summer’s 3D world-building tools.

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Shared rules

  • Pass exact scenePath and exact scene-root-relative node paths. Do not rely on editor selection.
  • Use one World3D. The tools fail closed across SubViewport-owned worlds.
  • Keep subjects bounded: placement/snap one subject, alignment sixteen.
  • Normal model-visible results stay below 5 KiB. Prefer targeted calls over collecting an entire scene.
  • Read-only tools never save: placement test, navigation probe.
  • Mutation tools register undo and save the exact target scene: snap, align/distribute.

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summer_test_placement

Input is a candidate global position and global Euler rotation. The subject’s current global scale is preserved, and the scene is not mutated. Interpretation:
  • Physics overlap counts are lower bounds because the physics server exposes no broadphase-completeness bit.
  • Any known obstruction makes fits: false.
  • Zero known physics overlaps can still yield fits: null; never coerce it to success.
  • grounded, signed floorGap, and support evidence are independent of overlap certainty. Claim physics-grounded only when floorEvidence is physics and supportQueryComplete is true; otherwise label the evidence approximate or incomplete.
  • visual_aabb includes visible mesh-only obstacles but is conservative.

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summer_snap_to_surface

The subject sweeps along a normalized world direction. Physics evidence uses enabled collider shapes; visual_aabb is a mesh-only fallback. When the engine answers with visual_aabb (no collider on the subject or the support), the tool re-measures the seat on visible triangles and reports evidence: visual_mesh with verify.final_gap; a prop without a collider is still invisible to physics. Use alignUp only when an exact collider support is intended. After the call, require evidence: physics, resolved contact, the expected supportPath, alignApplied, plausible slopeDeg, final gap/error bound, and the saved basis. The result does not expose the raw support normal or a heading residual, so use the saved basis plus an independent rendered/physics check. If overlap recovery fails, do not teleport manually through the obstruction.

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summer_align_distribute_3d

Anchors and extents come from visible descendant world AABBs. The solver translates only along the requested axis and preserves basis/scale. Distribution preserves caller order and fixed endpoints. This is one-dimensional arrangement evidence. It does not prove clearance on the other two axes.

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summer_navigation_probe

Iteration 0 is unready; iteration 1 and later can be queried. Layer-filtered snapped endpoints and the reported snap distances define what the engine actually tested. ready: false means unknown, not unreachable. Require both a reachable path and a small endpoint snap distance appropriate to the authored target. Probe every independent destination; one reachable subject does not validate the others. Derive the snap-distance threshold from the navigation agent radius or an explicit authored tolerance.
Source: library/skills/world-building-3d/references/spatial-tools.md, rendered from summer-engine@4.3.0 on npm.