MAJORFailure Reference

Vidu Physics Collapse — Pre-Generation Risk Reference

Technical Classification

Physics Simulation Constraint Violation

Physics Simulation Constraint Violation on Vidu occurs when the model violates Newtonian mechanics. Vidu has no explicit physics simulator — it learns physical behavior statistically. On prompts with complex fluid dynamics, gravity interactions, or multi-body collisions, the output frequently produces physically impossible motion. Worst after the 5-second mark where temporal coherence degrades.

How to identify this failure

✕Water, milk, or smoke flowing upward against gravity in Vidu output
✕Objects falling sideways or in the wrong direction
✕Collision between objects producing no physical response
✕Steam or vapor remaining static instead of dispersing
✕Cloth or hair moving against established wind direction

Real generation examples

Prompt used

"Coffee pouring into a glass, slow motion, soft daylight"

Failure observed @ 1.4s

Coffee stream curved upward at 1.4s, defied gravity for the remaining 3.6s

Prompt used

"Glass shattering on a kitchen floor, ultra slow motion"

Failure observed @ 0:02

Shards moved sideways with no downward gravity component at 0:02-0:05

Documentation strength

If you need to escalate

HIGH — Physics violations on paid Vidu generations are recognized as failure-mode credits.

AVA is a pre-purchase prevention tool, not a post-purchase recovery tool. Platforms generally do not guarantee credit refunds for output-quality failures; goodwill credits are at each platform's discretion. The strength rating reflects how well-formed your support ticket can be, not a promised outcome.

Prevention + documentation steps

01
Score your prompt before you generate
Run your prompt through AVA's pre-flight scoring against the Physics Simulation Constraint Violation pattern. Green light = generate. Yellow/red = rewrite using the suggested fix before you commit credits.
02
Capture Generation ID + timestamp if it failed anyway
Find the Generation ID in the URL or share link. Note the exact time when the Physics Simulation Constraint Violation first appears (e.g. "failure first visible at 1.2s"). Timestamped evidence is significantly stronger than a general complaint.
03
Use the correct technical term in your support ticket
Describe this failure as "Physics Simulation Constraint Violation". This term maps to a recognised internal workflow in the support system and routes the ticket to the right team.
04
Submit via the correct support channel
Runway has no direct email intake. Pro+ plan: open the in-app AI Assistant (help widget bottom-right of app.runwayml.com), describe the failure with the technical term, attach evidence. Free/Standard plan: human support isn't available — your channel is Discord #community-help with @On Call - Moderators.

Frequently asked questions

Why does Vidu produce water flowing upward?

The model has no explicit physics engine — it predicts pixel motion from statistical patterns in training data. When the prompt requires gravity behavior the training set is sparse on (extreme angles, slow-mo, partial occlusion), the predicted motion can violate gravity.

Are physics failures worse on longer Vidu clips?

Yes. Temporal coherence on physics simulation degrades significantly past 5 seconds. For physics-heavy prompts, keep clips ≤4s.

Does Vidu refund physics-collapse credits?

Yes when the report uses the technical term "Physics Simulation Constraint Violation" and includes a timestamp of the violation. AVA does this automatically.

Score your prompt

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