proven by the mech's own pods
The first fix (c5dfb00) negated x AND z. The operator challenged it:
'they couldn't hit rear panels AT ALL -- a 180 rotation couldn't explain
that' -- and a rotation would also have relocated rear damage, not
erased it, while the bench premise (the dummy faces its attacker) was
assumed, never measured.
The zero-premise probe (BT_ASPECT_TEST): four self-impacts at known
WORLD cardinals + one at each weapon's PHYSICAL MUZZLE position -- the
mech's own asymmetric geometry as the left/right anchor. Measured:
* WorldToLocal is a clean R(yaw), no hidden terms (yaws -30/150/40 deg
all consistent);
* our frame: RIGHT = +X -- SAME as the 1995 ring (W0/W7 = Right*) --
and FORWARD = -Z, flipped vs the ring's Front*-in-+Z-arc;
* under the pi rotation the pods CROSSED (left muzzle -> rtorso);
under z-negation every anchor lands its own side.
So: negate local z only, and -- since a reflection reverses angular
direction -- the SelectSlice torso-twist term flips sign with it
(twist was 0 in all probes; twisted-torso verify tracked on #124).
Anchor acceptance (fresh exe, third yaw): LRM15_1 left pod -> ltorso,
LRM15_2 -> right wedges, left/right arm muzzles -> larm/rarm, nose ->
front cells, tail -> rear cells, flank cardinals -> rgun / left wedges.
The BT_ASPECT_TEST probe + BTWeaponMuzzleWorld bridge stay as bench
scalpels.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>