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Josh Creek
ea756bd5ba
Six rounds of reward shaping (~700M steps) failed to produce upright ground driving. A critical review of the simulation rather than the reward found why: 1. The hull was a 1x1x4 box with inertia (1,1,1) and no restoring torque anywhere, so belly-down and rolled-90 were geometrically identical resting states. "Upright" was not a physically distinguished state at all - the reward was paying for a property the simulation did not have. 2. ~65% of episodes spawned ships via _random_position, which samples Y uniformly over the full 18m volume (mean ~8.7m). The measured airborne_fraction ~0.44 was largely that spawn distribution, and every ground-handling term fades out above 3m, so the shaping being tuned barely ever applied. 3. air_drill_chance 0.20 spawned deliberately unreachable-without-climbing states in the stage meant to teach ground driving, and its own air_touch_fraction (0.0002) shows the drills were never solved. Fixes land in the physics and the task distribution, not the reward: - ship.tscn: hull 1x1x4 -> 1.6x0.6x4 so it has one stable resting face; inertia (1,1,1) -> (7,1,7), physically correct for the hull, making tumbling reluctant while keeping yaw snappy. - ship.gd: new altitude-faded righting torque (spring-damper toward belly-down, faded out by 3m so aerials keep full attitude freedom). This is the grav-plating analogue of Rocket League's auto-righting and helps human pilots land cleanly too. - training_mode.gd: new ground_start_chance branch spawning ships level and resting on the floor with a floor-level ball - the state the handling stage's rewards are actually written for. - generation5.py: ground-start-chance 0.50, air-drill-chance 0.20 -> 0.0. Reward terms are left exactly as they were; they should finally pull in a direction the ship can go.
