nx_bvh_lib.nx

nx_bvh_lib.nx -- SHARED BVH (BioVision Hierarchy) PARSING SUBSTRATE. Extracted 2026-08-07 when the second consumer appeared (nx_bvhfk, forward kinematics) rather than copy-pasting the tokenizer into it -- Rule 15, and Rule 9: this library PARSES, it does not interpret. Kinematics, census and rendering are separate organs on top of it. NAMING: nx_bvh.nx is a BOUNDING VOLUME HIERARCHY for the slicer. This file and its consumers are the MOTION-CAPTURE bvh. The collision already cost one false capability reading. *THE FILE CARRIES ITS OWN ANSWER KEY: a BVH declares a joint tree whose CHANNELS sum to an exact per-frame width, then prints rows of that width. b_motion PROVES that identity before returning, so a hierarchy parse that is wrong by a single channel REFUSES instead of silently mis-slicing every frame. Verified against two independent real files (19 joints/60 chan/455 frames = 27,300 values; 55 joints/168 chan/69 frames = 11,592 values), both exact. UNITS ARE DECLARED, NEVER IMPLIED: OFFSET + positional channels = file units x B_SCALE (1000). BVH does not state its unit in the format; the convention is centimetres, so we do NOT claim mm. rotational channels = degrees x B_SCALE (1000) = millidegrees. frame time = MICROSECONDS (x B_TSCALE); fps is DERIVED, never assumed 30. license_tier: ORIGINAL No hw writes (Rule 26).