sdf_csg op• Data kinds: coordgrid → sdf
• Call: import fullseye as fs; fs.ledger.cylinder_sdf(grid, center, axis, radius, height) (to call the implementation directly, import sdf_ops; sdf_ops.cylinder_sdf(grid, center, axis, radius, height); from the registry, ops3d.get("cylinder_sdf"))
Exact signed distance field of a finite-length cylinder (flat caps at both ends) (negative inside, positive outside).
Split into the axial distance t and the radius from the axis r, set q = (r - radius, |t| - height/2), and take outside = ‖max(q, 0)‖, inside = min(max(q), 0), sdf = outside + inside. This applies the same Quilez-style construction as box_sdf to "the 2-D cross-section (radius, axis)", so it is the true Euclidean distance to the side, the caps and the corners (rims) alike.
Arguments and validation (ValueError):
• grid: float array (..., 3) whose last axis is 3.
• center: the center of the cylinder (the centroid, not an end face; 3 elements).
• axis: axis direction (3 elements, zero vector and NaN are rejected; length is normalised automatically).
• radius: scalar equivalent to radius > 0 (0 is the axis line itself, negative is rejected).
• height: scalar full length (±height/2 from center; negative is rejected).
Returns: float64 of shape grid.shape[:-1].
Where to use: a through hole is sdf_subtract(part, cylinder_sdf(...)) (make height longer than the part so no rim of the end face remains). Bosses, pins and shafts use sdf_union. If you need an infinitely long cylinder, take height large enough (once the end faces are outside the evaluation domain, only the side matters).
• 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.
• 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_intersect · sdf_subtract
sdf_csg)grid_coords · sphere_sdf · box_sdf · plane_sdf · torus_sdf · capsule_sdf · sdf_union · sdf_intersect
*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.