MPIE-Bench: Benchmarking Anatomically Plausible Multi-Person Interaction Editing

MPIE-Bench evaluates multi-person image editing in contact-heavy actions such as embracing, carrying, and grappling, where fused limbs, missing extremities, and body interpenetration remain common. The benchmark contains 2,500 video-mined editing triplets across 405 scenes, 14 interaction categories, and four contact-density levels. MPIE-Eval introduces mesh-based Anatomy and Interaction axes using a frozen public multi-person mesh reconstruction. Across ten editors, the best reported scores reach only 0.65 for Anatomy and 0.72 for Interaction, while VLM checklist scores exceed 0.95. A five-rater study reports closer alignment with human judgments.