nx_loop_subdiv.nx

nx_loop_subdiv.nx -- LOOP SUBDIVISION (Charles Loop, 1987): the triangle-mesh SMOOTH-LIMIT subdivision scheme. Unlike linear midpoint refinement (nx_subdiv sd_subdivide, which keeps original vertices FIXED = same silhouette, only more triangles), Loop REPOSITIONS even (original) vertices toward the neighbour centroid, and weights each new odd (edge) vertex by the two OPPOSITE vertices (3/8(a+b) + 1/8(c+d)) -> the mesh converges to a smooth limit surface (a coarse octahedron -> a round blob). Integer fx256, deterministic. This is the census GAP "no Catmull-Clark smooth-limit subdivision" answered for triangle meshes. license_tier: ORIGINAL