Download the exact captured file
--- name: deterministic-motion-rendering description: >- Provides offline animation and video export guidance when rendering scenes frame by frame, seeking arbitrary frames, or verifying reproducible fixed-timeline media. Covers scene readiness, frame evaluation and exported media evidence rather than ordinary live UI interaction. tags: - offline-rendering - motion-graphics - frame-export - reproducibility --- # Deterministic Motion Rendering Render a declared scene state for a requested frame, independently of capture speed or the order of previous requests. Keep creative decisions separate from the machinery used to capture them. These contracts are Coacus conventions informed by the sources in the references, not guarantees of identical pixels on arbitrary machines. ## Establish the contract Record the scene revision, input assets, seed, dimensions, frame rate, frame count and delivery format. Preserve the requested specification; do not impose a universal frame rate or silently retime content to match it. Separate three operations: prepare required resources, evaluate the requested frame, then capture its completed output. Keep wall clocks, live network data and uncontrolled randomness outside scene evaluation. For simulations, either evaluate directly or reconstruct from a known initial state with fixed steps. Test repeated and shuffled frame requests before committing to a full export. Load only the reference needed for the current operation: - For fonts, decoded images, video and asynchronous scene resources, use [scene readiness](references/scene-readiness.md). - For exact frame domains, randomness, seeking, technology adapters and subframe sampling, use [timeline and sampling](references/timeline-and-sampling.md). - For capture records, external encoding recipes, decoded-output inspection and acceptance evidence, use [reproducibility and review](references/reproducibility-and-review.md). For an animated technical diagram exported from an editor, use [diagram export adapters](references/diagram-export-adapters.md) to reconcile endpoint samples, frame caps and output timing with the delivery contract. ## Preserve ownership Use [interactive motion](../ui-motion-interaction/SKILL.md) for live controls, gesture interruption and canonical timing tokens. Use [GPU graphics](../../../engineering/practices/ui-gpu-graphics-web/SKILL.md) for canvas, shaders and scene implementation. A scroll-controlled player of an existing image sequence belongs to [scroll-driven motion](../ui-scroll-driven-motion/SKILL.md), even when this skill produced its input frames. Apply the existing [web accessibility](../../../engineering/practices/web-accessibility-wcag/SKILL.md) requirements to the player and presentation context. An exported video's frame rate does not establish interactive responsiveness or accessible playback. ## Report evidence honestly Distinguish scene-state equality, decoded-pixel equality and final-file identity. Name the environment and comparison method for each claim. Record missing resources and unexecuted checks; a plausible recipe is not a successful export. Review narrative continuity and legibility separately from technical validity.