render op• Data kinds: normalmap → image2d
• Call: import fullseye as fs; fs.ledger.brdf_lommel_seeliger(normals, light=(0.0, 0.0, 1.0), view=(0.0, 0.0, 1.0), w: 'float' = 0.42) -> 'np.ndarray' (to call the implementation directly, import render_shade; render_shade.brdf_lommel_seeliger(normals, light=(0.0, 0.0, 1.0), view=(0.0, 0.0, 1.0), w: 'float' = 0.42) -> 'np.ndarray'; from the registry, ops3d.get("brdf_lommel_seeliger"))
Shade a normal map with the Lommel-Seeliger reflectance law (regolith that stays bright to the limb) and return I/F (H, W).
Lambert (the diffuse term of phong_shade) goes to 0 at the limb (μ→0), but Lommel-Seeliger is μ0/(μ0+μ), so it stays bright at μ0 even at the limb, giving the "flat disc" look of asteroids and the Moon. w = single-scattering albedo. fail-closed (normal shape, range of w).
The computation is identical to model='lommel_seeliger' of brdf_shade: for each pixel it takes μ0 = clip(N·L, 0, 1) and μ = clip(N·V, 0, 1), and returns I/F = π · (w/4π) · μ0/(μ0+μ) (= (w/4)·μ0/(μ0+μ)). Pixels where μ0 or μ is 0 or less (faces not lit, faces turned away from the line of sight) are 0.
• normals: float (H, W, 3). Vectors of length 0 are treated as background and give output 0 (the normals of render3d.render_mesh can be passed as is). Normalisation is done internally.
• light / view: direction vectors pointing surface→light source and surface→viewpoint (normalised internally). The camera looks along -Z by convention, so the default is view=(0,0,1). Parallel-light, orthographic approximation; the directions are constant across the image.
• w: single-scattering albedo; anything outside (0, 1] raises ValueError.
Returns the I/F as float64 (H, W). With orthographic projection and light == view (phase angle 0), μ0 = μ and the whole foreground takes the uniform value w/8. Values lie in [0, w/4) and are not normalised to [0,1]. For highlights use phong_shade; to include the opposition effect and roughness use brdf_hapke.
• blender_interop — Using Blender alongside — build the shape, measure it with fullseye (pitfalls: axes, units, ground truth)
• 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.
• itokawa_regolith_hero — py -3.11 examples_3d/itokawa_regolith_hero.py
image2d as input)fuse_to_voxel · fit_poly_surface · eval_poly_surface · surface_form_error · background_flatten · polar_unwrap · fit_zernike · matcap_shade
render)project_points · render_point_depth · render_volume_projection · render_shaded · ambient_occlusion · cast_shadow · phong_shade · matcap_shade
*Provenance: render_shade.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.