Static Geometry and Moving Subjects Stopped Sharing One Judge

WorldAlign separates two kinds of 4D consistency that a single reward can blur. Static regions are checked through semantically masked geometric reprojection, with an additional camera-motion reward to discourage trivial stillness. Dynamic subjects are judged by sample-specific checklists covering motion, physical plausibility, shape and texture. Online post-training with these decoupled rewards improved both static and dynamic consistency across two image-to-video generators without suppressing reported motion. The dynamic component still relies on a vision-language model as judge, so the result is evidence for a better reward design rather than a direct measure of physical truth.