sdf_csg op• Data kinds: sdf × sdf → sdf
• Call: import fullseye as fs; fs.ledger.sdf_smooth_union(a, b, k) (to call the implementation directly, import sdf_ops; sdf_ops.sdf_smooth_union(a, b, k); from the registry, ops3d.get("sdf_smooth_union"))
A smoothly rounded union (polynomial smooth-min). k>0 rounds the seam with a radius of about k.
Inigo Quilez's quadratic polynomial smin:
h = clip(0.5 + 0.5*(b-a)/k, 0, 1), smin = mix(b,a,h) - k*h*(1-h).
Properties: (1) symmetric smin(a,b)=smin(b,a), (2) smin <= min(a,b) (dips at the seam),
(3) equals min(a,b) as k→0 (= hard sdf_union), (4) homogeneous of degree 1
smin(s*a,s*b,s*k)=s*smin(a,b,k) (scale-consistent).
k is the rounding radius in distance units. If you want a hard min, use sdf_union. For input containing ±inf (interoperating with the "+inf if everything is free" contract of esdf), the blend band |a-b|<k degenerates, so it returns exactly min(a,b). Raises ValueError for k<=0 (fail-closed to avoid division by 0).
• 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.
• render_beauty — py -3.11 examples_3d/render_beauty.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 · 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.