Rapier replay diagnostics
Turns an intermittent physics failure into a recorded sequence that can be compared. It captures starting conditions and operation order, distinguishing observed repeatability from an unsupported promise of universal determinism.
rapier-diagnostics-replay
See how it helpsWhen is it useful?
Use it when physics diverges between runs and you need to isolate creation order, input scheduling or application math.
What does it help you do?
- Records initial state, creation order, inputs and step count.
- Compares equivalent ticks and separates application nondeterminism.
- Profiles bodies, contacts and queries before lowering physics quality.
Try asking this
Our pinball ball occasionally exits the table. Record initial bodies, creation order, inputs and simulation ticks, then replay twice and compare the same tick. Change only rendering frequency and explain whether divergence comes from our timing, input order or an unresolved engine-specific limitation.
Detailed documentation
Read the skill’s original instructions, examples and checks in their authored language.
Show less
Rapier — diagnostics replay
Use when diagnosing Rapier divergence, crashes, physics performance or replay/snapshot behavior.
Version and project gate
Inspect Rust crate features or JS/WASM package and version, 2D/3D choice, framework wrapper version, units, solver settings, timestep ownership, body/collider handles and render synchronization. Determinism depends on binding, version, initialization and operation order. Never turn a task into an engine upgrade without the user’s intent. Read the version-matching official reference when an API decision depends on it.
Work
Capture binding/version, initial state, object creation order, inputs and timestep count. Compare snapshots or state at equivalent ticks where supported. Separate nondeterministic application math from engine guarantees. Profile active bodies, contacts and queries before changing physics quality.
Deliver
A minimal replay and an evidence note distinguishing observed determinism from assumed guarantees. Keep the change in the existing project structure; separate actual observations from the proposed acceptance scenario below.
Failure to prevent
JS/WASM guarantees do not automatically apply to every native build or math operation; seed alone does not define operation order.
Acceptance scenario
Replay the same recorded sequence twice, compare a known tick and vary the render schedule without changing simulation input order. Follow the project’s execution and verification permissions. If execution or a target device is unavailable, provide the reproduction steps and name the remaining uncertainty; do not mark it passed.
Scope and sources
This skill belongs to Vector. Agent selection is restricted by Orqestria’s assigned-agent policy, including forced skill selection; instruction text alone is not an access control. These are original task workflows researched from official documentation, not a copied or endorsed vendor skill.
Included files 1
SKILL.md