A physics reward can improve video generation without creating a real physics engine

Dapper-Drawer4546 · reddit · 2026-07-22

The post argues that a physics reward is not the same thing as a physics engine.

It uses LingBot-Video as the example: the model's training reward includes physical rationality and task completion, which can discourage obviously impossible motion. But that does not mean the system has explicit simulation components such as mass, friction, collision geometry, or a numerical integrator.

The author says the right way to test such a system is with controlled experiments:

Even if that works, it would only show learned dynamics, not proof of a general-purpose physics engine.

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