MAJORFailure Reference

Luma Dream Machine Physics Collapse — Pre-Generation Risk Reference

Technical Classification

Physics Simulation Constraint Violation

Luma's fluid and particle physics is its single most visible weakness. Generations that involve water, smoke, fog, dust, hair, or any soft-body simulation frequently produce non-physical behavior — fluid inversion, smoke moving against airflow, particles that interpenetrate solid surfaces. The model has clearly seen these phenomena in training but lacks a real physics constraint at inference time, so the output drifts toward "plausible-looking-pixels" rather than "physically-coherent-motion." For a support ticket, this category has high precedent — Luma support recognises Physics Simulation Constraint Violation as a documented failure mode.

How to identify this failure

✕Water flowing upward or sideways without gravity cause
✕Smoke or fog moving against indicated air direction
✕Falling objects that pause mid-air before resuming
✕Cloth interpenetrating bodies or solid props
✕Particles drifting in opposite directions within the same frame

Real generation examples

Prompt used

"Slow-motion water fountain exploding upward, cinematic"

Failure observed @ 0:03

Water at 0:03 reverses direction, falls UPWARD against gravity, then resumes downward at 0:04

Prompt used

"Smoke rising from a campfire on a still night"

Failure observed @ 0:01 → 0:03

Smoke drifts left at 0:01, right at 0:03 without wind cue; net motion incoherent

Documentation strength

If you need to escalate

HIGH — Luma support recognises physics failures as a documented escalation category; well-timestamped reports approve in 1-3 business days.

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

Will Luma support response credits for physics failures?

Yes. Cite "Physics Simulation Constraint Violation", include the Asset ID, attach a PDF audit report or video clip showing the timestamp where physics violates. Luma support has escalation precedent for this category.

Why does Luma struggle with physics?

Video diffusion models learn appearance correlations from training data — they don't maintain a runtime physics constraint solver. Without explicit physical priors, fluid, smoke, and particle motion drift toward visually-plausible but physically-incoherent trajectories.

Which prompts trigger physics failures most often?

Slow-motion water, smoke trails, soft-body materials (cloth, hair), falling objects, complex camera motion through fluids. AVA flags these prompt patterns as high-physics-risk before you spend credits.

Catch it before you generate

AVA scores this failure mode against your prompt in real time

Free Chrome extension. Analyzes your prompt as you type, flags failure-prone patterns specific to this model, and tells you what to rewrite — before you commit credits to a generation that will fail.

Install free All 105 failure modes

AVA Pro · founders' round

$50 for 6 months of unlimited scoring across all failure modes + personal failure-history dashboard. Locks in $13/mo grandfathered after.

Claim $50 founders