**Overall Verdict:** Accept — The submission defines a coherent, professionally substantial reconstruction task with complete numerical references and explicit safeguards against shortcut solutions; no material submission defect was established.

**Completeness Check:**

- Instruction: Complete — Deliverables, timing, calibration, passive dynamics, prohibited shortcuts, and offline regeneration requirements are explicit.
- Inputs: Complete — The video, camera calibration, scene dimensions, and output specification are supplied and structurally consistent.
- Toolchain: Complete — Procedural source, vendored simulation engine, dependency versions, executable build script, and an Apache-2.0 license provide a plausible single-machine CPU workflow.
- Reference output: Complete — Separate material trajectories, ten mesh archives, calibrated camera, and rendered video cover the required artifacts.
- Rubric: Complete — Weighted metrics, material-specific hard limits, malformed-output rejection, rebuild comparison, and mandatory visual audits define success objectively.

**File and Task Reachability:**

Attachment classification: `partially_reachable`. All 12 manifest attachments were downloaded at their declared sizes and inspected: TASK.md, FORMAT.md, scene_facts.json, both camera.json files, reference.mp4, render.mp4, evaluate.py, requirements-lock.txt, solution.zip, dynamics.zip, and meshes.zip. Archives were safely inventoried and passed internal integrity checks.

Both materials contain finite float32 trajectories shaped `(49, 2052, 3)` with separate mesh identifiers. Every mesh supplies valid vertices and triangle indices for all 49 frames; eight meshes remain exactly static. Sand geometry centers agree with its trajectories. Camera files are identical and contain a valid pose. Both videos are byte-identical, with container metadata specifying H.264, 640 × 400, 49 frames, and 32 fps.

Video decoding and visual inspection were unavailable. Evaluator execution, offline regeneration, and rebuilt-array agreement were not verified. Two supplementary documents referenced by the README are absent; their contents remain unreviewed.

Task classification: `reachable`. The supplied inputs support reconstruction, procedural simulation, surface extraction, rendering, and export. Evaluation combines private numerical comparison with isolated rebuilding and calibrated/novel-view geometry audits. Reference source and ground truth are explicitly excluded from solver access.

License keys, accounts, tokens, and other credentials are not required from the contributor. Confidential, proprietary, or internal material may be evaluated as submitted evidence without requiring additional disclosure.

**Special Screening:**

None. No affirmative evidence supports a screening label. Public benchmark provenance and exact software-release availability were not independently verified because approved external search was unavailable.

**Recommended Changes:**

The calibrated inputs, persistent material references, and explicit manual gates form a strong evaluation package. No required changes were identified. Optionally, make the README self-contained by incorporating its referenced setup and simulation-limitations documentation.