f481ccbb5f
The three sections recorded as undecoded are fixed-stride arrays and counts[0..2] are their record counts: 12, 96 and 48 bytes. Section 1's remainder is exactly 0 in 11/11 objects and section 2's exactly 96 in 11/11, which is what makes these strides rather than a coincidence of division. Section 0 is a point list: 13467 of 13467 records lie inside their object's own header bounding box. Section 2 is a plane list, 12 f32: four zeros, a unit normal (|n|=1 in 133573/133573), a signed distance, a point inside the bbox (133573/133573), and a trailing 1.0 (133573/133573). The decisive check is algebraic -- n.p + d must vanish for a real plane, and over all 133573 records the relative residual has a median of 2.29e-08 and a maximum of 2.15e-07. That is float round-off, not a fit. So a REGN object carries a point list and a plane list beside its uniform grid, which fits collision or region-boundary geometry and sits next to MCOL. Still open: section 1 (96 B, 60631 records), what queries the planes, the zeros at [0..3], and the constant 96-byte tail.