4DGS scene v3 — binary test of quality ceiling, regression confirmed
TASK-105 binary test: data enrichment retrain. Naive temporal-only expansion (10 frames + 121 Wan motion frames at fixed camera) caused REGRESSION — train PSNR 30.5 (locked в overfit), test PSNR 13.16 (vs v2 25.4). v3 rolled back, v2 restored as production. Ceiling confirmed: 4DGS-from-scratch на synthetic data cannot generalize beyond training distribution без diverse spatial+temporal sampling. CAP4D-class diffusion-trained 4DGS = real path forward (FLAME owner unblock pending).