sdf_csg op• Data kinds: sdf × sdf → sdf
• Call: import fullseye as fs; fs.ledger.sdf_intersect(a, b) (to call the implementation directly, import sdf_ops; sdf_ops.sdf_intersect(a, b); from the registry, ops3d.get("sdf_intersect"))
The intersection of two SDFs, A∩B = the element-wise max(a, b) (inside only where both are inside).
The zero isosurface is the intersection of both boundaries. Exact SDF outside, conservative lower bound inside.
Computation: np.maximum(np.asarray(a, float64), np.asarray(b, float64)). Being an element-wise max, a point is inside A∩B (negative) only when a < 0 and b < 0. The shapes only need to be broadcast-compatible (otherwise numpy raises ValueError), and nothing else is checked. NaN propagates, ±inf propagates exactly (max(a, -inf) = a).
Input: 2 SDFs evaluated on the same grid (outputs of sphere_sdf / box_sdf / esdf etc., negative inside, positive outside). The distance unit is that of the input.
Returns: float64 of the broadcast shape. <= 0 is the occupancy of A∩B.
Notes:
• The outside value can come out smaller than the true distance: outside the intersection, when the point is outside A and outside B, max(a, b) is the distance "to the farther surface", and the surface of A∩B may be farther than that (lower bound). The zero isosurface is exact.
• If there is no common part, every element is positive (occupancy 0); this is not an error.
• Used for CSG "cut-outs", such as trimming a sphere with a box or building a prism from 2 boxes. Removing B from A is sdf_subtract.
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• gear_metrology — py -3.11 examples_3d/gear_metrology.py
• render_beauty — py -3.11 examples_3d/render_beauty.py
• sdf_csg — py -3.11 examples_3d/sdf_csg.py
sdf as input)sdf_to_occupancy · fuse_to_voxel · integrate · extract_surface_points · query_distance · sdf_union · sdf_subtract · sdf_smooth_union
sdf_csg)grid_coords · sphere_sdf · box_sdf · plane_sdf · cylinder_sdf · torus_sdf · capsule_sdf · sdf_union
*Provenance: sdf_ops.py — 3D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.