Cut 5's own probe passed while breaking Cut 3's reuse rule: with R7 holding
the rim, the through-thickness echo (KEcho/_EchoReflect) is the only
remaining source of sub-critical tension for a weak hit, and its magnitude
(-0.65) was weaker than the still-live residual compression velocity left
by the direct KInject kick by the time the echo fired. The echo's own
header comment says a free-surface reflection inverts with unit
magnitude, matching the pre-R7 rim's Dirichlet condition -- -0.65 was a
lossy fraction that could reduce but never flip the sign of u, so a weak
hit's u never crossed positive and KFracture's `u <= 0` guard skipped the
sub-critical erosion branch forever, no matter how many hits landed.
Raised echoReflect from -0.65 to -0.9 (ShieldPanel.cs) -- enough margin to
flip a weak hit's residual compression into net tension without needing a
delay/seeding change; echoDelaySteps and KInject's seeding were not the
defect. All four probes now pass, including Cut 3's reuse rule (temper
0.4180 -> 0.3997 on a reused panel).
Also lands the multi-hit-reuse rule Cut 5's own report flagged as unpinned:
CheckRepeatedWeakHitsBreakWhereOneDoesNot in ShieldPanelCut5Verify.cs.
Energy 15 (not 8, whose peak tension of ~0.14 sits under tensileStrength
0.2 and can never break at any repetition) breaks on hit 2 of a live,
reused panel while a cold single hit -- given equal idle time (720 steps,
matching the multi-hit run's total budget, to rule out "just needed more
time to ring out") -- never breaks. This is the Cut 3 reuse rule and the
temper mechanism producing the operator-facing payoff together.
Verified: ShieldPanelCut1Verify, Cut2Verify, Cut3Verify, Cut5Verify all
PASS via batchmode (graphics device required, not -nographics).
Operator watch: echoReflect at -0.9 is close to the physical "unit
inversion" ceiling implied by the header comment; if later tuning raises
hit energies or lowers damping, watch for the echo overshooting into an
immediate break on a single moderate hit (observed at -1.4 and even -1.0
in earlier tuning passes) rather than the intended multi-hit erosion.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
R7 (operator ruling): the panel's emitters hold its edge, so the rim is no
longer a free surface. Deletes the openW ghost term end to end -- its only
consumer in ShieldSim.compute's Laplacian, and the accumulation loop in
TilingBuilder that built it -- rather than zeroing it at runtime. A broken
cell's own faces are untouched (KWaveStep's per-edge `solid` check already
treats a broken/ungrown neighbour as free), so the dicing cascade survives.
D9: v was unclamped while u was, so a hard hit drove v far past what one
substep's u-clamp could absorb, pinning u in compression indefinitely (the
measured collapse above energy ~60). Added `_VelClamp` and clamp v to it
every substep in KWaveStep, exposed as ShieldPanel.velocityClamp (100).
D10: KFracture dispatched once per frame but read `_Dt` still holding the
substep dt from the wave loop, so damage and temper erosion accrued at
1/substeps of the intended rate. Fracture's clock is the frame it settles
once per, not the substep, so it now gets the frame dt -- one line, not the
five-extra-dispatches-per-panel alternative (dispatch count is the measured
per-panel cost at up to 12 live panels).
D15: zero-init BuildLine's output struct so the compute compiler's dataflow
analysis stops flagging every branch as a potential non-initializer.
Tuning (ShieldPanel.cs Material header): tensileStrength 0.9->0.2,
temperErosion 2.2->12, damageGain 6->100, breakAt 0.75->0.08,
storedEnergyGain 0.8->1 -- makes a solid hit dice a local cluster around
impact, a weak hit leave nothing, and repeated weak hits erode temper
substantially without breaking anything outright.
Adds ShieldPanelCut5Verify (batchmode probe, same pattern as Cuts 1-3):
pins monotonic peak tension against energy (no D9-style collapse), solid
vs. weak hit outcomes, temper erosion under repeated sub-critical hits,
breaks clustering at the impact rather than the rim (R7), and a broken
cell's neighbours breaking more often than distant cells (the cascade).
D9 and D10 mutations were manually reverted and confirmed to fail their
respective checks; R7's reintroduced-rim mutation did not reliably fail
the cluster check within this probe's energy/step budget -- noted as a
known gap rather than papered over.
The map's own operator-level check ("repeated hits on the same spot break
through on a later hit than the first") is left to play: a closing hit
landed after several prior weak hits on one live panel instance measured
a materially lower peak tension than the same energy against a fresh
panel, a reproducible multi-hit interaction this cut did not chase to
ground.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Meta Vens