# SE212 authored arm rig F

Status: delivered authored review candidate. The changed211-frame interval is
reviewed; full-system qualification and owner adoption remain open.
The original r12, the E7 candidate and all adopted releases remain preserved.

## Native file

Delivery file on Windows:
`C:/mozu/se212/repo/output/rig_candidates/siteat212_20260925/authored_rig_20261003/mozu-siteat212-authored-arms-f-full.blend`.
SHA256: `6e279ed197f052fcf3956437968092ee39c689800f78e24a86304d69b3ebf1c8`.
The complete221551322-byte native stays on Windows under the owner's resource rule.
It opens at frame139, with Sit then eat selected, action mode3, and the complete
frames1–879 at60fps. Normal playback requires no new Python frame handler.

The reviewed opening is frames1–211. The separate working native
`mozu-siteat212-authored-arms-f.blend` remains preserved, SHA256
`c1ccaac26eb9987e690a41ab3fc9aa0d805b8d0640c9d714159f93eee7d32598`. Delivery changes only the
scene playback end from211 to879. Eight complete geometry hashes match before
and after reopening, including frames439 and879; both shoulder controls change
geometry and reset exactly. See `native-delivery.json`. The original action
already contained879 frames; it has not been expanded by interpolation.

## Design

The five original reference clips are read by task: balance during descent,
release after sitting, and quiet support while the head approaches the food.
Independent front/side generated videos are not synchronized measurements.
The sitting rest rule is the owner's standing-arm appearance, not a compromise
between incompatible generated endpoints. No numerical pose search or mechanical
source fitting is used in this revision.

The original2018-vertex arm material scaffold and radius profile are retained.
A length-preserving material-frame sweep reuses the proven broad elbow model.
The original standing length is0.8390248 units. The shoulder is bound to the real
body surface at standing rest, with the original offset; it is not keyed through
arbitrary world positions. A fixed radius profile carries the original hand volume.

## Live controls

Select either original arm and its `SE212F | Standing-preserving articulation`
Geometry Nodes modifier. The modifier remains unapplied.

| Control | Meaning |
| --- | --- |
| Swing | Shoulder forward/back rotation, degrees |
| dRaise | Shoulder opening relative to standing, degrees |
| dForward | Shoulder plane offset relative to standing, degrees |
| Elbow | Broad elbow bend, degrees |
| Elbow softness | Width of the bend along the arm; default0.55 |
| Elbow center / plane | Bend location and orientation |
| Wrist / Wrist side | Hand bend relative to the forearm, degrees |
| Paw roll | Axial hand roll, degrees |
| dBend | Existing whole-arm curvature offset used at the eating boundary |
| Original blend | Frames171–178 transition to the existing eating geometry |

`SE212F | Sit arm performance` exposes Enabled. Set it to0 to recover the complete
original arm. Modes0–2 bypass the extension. This candidate is authored for
`SE212 | Sit then eat` in mode3; disable the extension before choosing another
mode3 action such as standalone Eat. The layer does not identify arbitrary action
names automatically.

The reviewed defaults are animated. Use the relevant arm action/keyframes when
editing motion; playback restores keyed values. Wrist and roll are independently
editable. The reopened file passed actual shoulder, elbow, wrist and roll changes
and exact reset on both sides. Do not infer a general all-combinations safety
limit from these individual control tests.

## Timing and eating boundary

There are14 authored keys with monotone C1 Bezier scalar interpolation:
anticipation, forward balance, shoulder opening for release, lowering beside the
body, rest, then an authored food-support approach. No source-coordinate objective
or optimization is involved in building the keys.

Rest frames91–141 preserve the standing shape, translated with the shoulder.
The later food-support task intentionally meets the original longer eating arm;
fixed standing length is not claimed across that transition. From frame178 the
original evaluated arm is selected exactly. The existing eating performance and
its later food/head contact limitations therefore remain separate from this change.

## Source and reuse

The source is `seated_authored_native.py`, supported by `seated_authored_rig.py`,
`seated_authored_sweep.py` and `seated_authored_timing.py` in this lane's research
folder. The body-triangle binding and stored `c12_material` / `c12_ring` attributes
are tied to the original topology and vertex order. Source topology changes require
regenerating or explicitly transferring them. The small hidden ring objects are
live integration scaffolds and must remain in the file.

The supplied controls are native Blender authoring controls. No skeletal-only
export or another runtime has been verified. Start edits from a new copy; do not
overwrite a candidate or an adopted release.

## Rebuild sequence

Use a separate candidate checkout/output version. The native builder refuses to
overwrite an existing F file. Keep the hash-bound r12 parent and
`round2/pilot-report.json`: its `parentHoldMapping` contains the direct conversion
of the existing food-hold controls, not fitted source coordinates. Native build
inputs and source versions are recorded in `build-provenance.json`.

Submit Blender/media commands through the shared Windows FIFO as owner `se212`,
one owned job at a time. From the repository root, run these stages in order:

1. Blender: `seated_authored_native.py` creates the editable native and verifies
   save/reopen, original bypass and individual control edit/reset.
2. Blender: `seated_authored_capture.py` creates the17-pose multi-view preflight;
   Windows Python: `seated_authored_media.py` creates its JPEG boards.
3. Blender: `seated_authored_audit.py` measures temporal joins, rest parity,
   topology, grip and the bypass for other locomotion modes.
4. Blender: `seated_authored_capture.py -- --full` captures the changed interval;
   Windows Python: `seated_authored_media.py --full` creates the60fps videos and
   every-frame boards. Do not replace visual review with geometry checks alone.
5. Blender: `seated_authored_delivery.py` saves a separate full-range file and
   verifies geometry plus an editable shoulder after reopening it.
6. Pull only the small media/reports to Mac. Run `seated_authored_page.py` after
   writing the review and guide; it requires the complete media and delivery proof.

All named scripts are under `scripts/research/siteat212_20260925/`. The exact
Blender command pattern is `blender.exe -b --python-exit-code 1 --python <script>`;
pass script flags after `--`. Retain the5GB free-space floor and all source files.
The14 authored poses and interpolation are in `seated_authored_native.py`; a new
performance edit changes those semantic controls, followed by a new native version.

## Review limits

The standing arm already intersects the hidden body core. The seated rest retains
that visual design. Raw zero-clearance measurements remain failed and are recorded;
standing shape parity is not proof of collision freedom. Hand visibility can also
change when seated feet occlude the arm in the front view. Read FINAL_REVIEW.md and
the native reports for the measured scope and unresolved issues.