GLM-5.3 Edges Space Bunny Alpha in Physics Simulation Test
Head-to-head physics benchmarks remain rare, and this one suggests GLM-5.3 holds an edge over an unnamed stealth competitor on collision-accurate simulation. Builders testing video or world models can replicate the 5-scene setup to compare candidates on dynamics rather than visual polish. The stealth model's OpenRouter availability makes it easy to verify the result firsthand.
A 5-scene physics test run by @aimlapi showed GLM-5.3 beating Space Bunny Alpha on a Newton's cradle scenario. Space Bunny Alpha is a stealth model launched on 29 Jan 2026 via OpenRouter and OpenCode, offering a 1-million-token context window and native multimodal input. In the harder tornado and water drop scenes, neither model performed well. The test's author noted that visual results are constrained by the dynamics, so incorrect collision timing or momentum transfer cannot be masked by adding environmental detail.
GLM-5.3 beat Space Bunny Alpha (the new stealth model launched today) on Newton’s cradle in a 5-scene physics test done by @aimlapi .
Space Bunny Alpha is currently stealth, launched on OpenRouter/OpenCode, with a 1-mn token context window, native multimodal input, strong coding performance.
The tornado and water drop were even harder. Neither model handled those well.
visual result is constrained by the dynamics. you can't compensate for incorrect collision timing or momentum transfer by adding more detail to the environment.
