# R1 Selective: lineage and concrete changes

This continues the existing v30-Polished-R1 task. “30B” was a typo for v30, not a previously accepted revision. The recommended branch is separate from the failed first-pass full-skin candidate.

## Authoritative inputs

- **v30 manufacturer handoff:** mechanical dimensions, exact frozen electronic/hardware/approved mechanism references and mounting datums. The recompute subset is byte-identical and recorded in `inputs/input-lineage.json`.
- **v31:** useful module organization and source-solid cleanup patterns. It was not treated as an already solved silicone, mesh or wiring revision. No live Fusion execution is claimed.
- **Professional September 20:** separate larger reference. Supplied measurements are 80 ×150 mm shells and an 84.2 ×154.2 ×28 mm rim. Only architectural ideas were considered; nothing was scaled into v30.
- **Chalk & Ember:** appearance intent, not dimensional authority.

The supplied v30 electronics configuration is the complete working mechanical set, as confirmed by the user. No previous separate Taoglas antenna or coax is required. Physical procurement identity, approved pinout and powered tests are not independently confirmed by this CAD work.

## Local section comparison

| Section | v30 source rigid material | Failed full-skin candidate | Recommended selective candidate |
|---|---:|---:|---:|
| Four PCB rear-relief centroids | 1.210223 mm | 0.860223 mm rigid +0.30 mm skin | Original 1.210223 mm rigid, exposed rear; no skin |
| Connector-lead relief | 1.315 mm | 0.865 mm rigid +0.40 mm skin | Original 1.315 mm rigid, exposed rear; no skin |
| Sampled main rear panel | 2.000 mm | 1.250 mm rigid +0.70 mm skin | Original 2.000 mm rigid, exposed rear |
| Battery rear seat | 2.400 mm | 1.650 mm rigid +0.70 mm skin | Original 2.400 mm rigid, exposed rear |
| Volume-side control land | 1.370 mm | 0.970 mm rigid +0.35 mm skin | Original 1.370 mm rigid, exposed control land |
| Sampled plain side wall | 2.750 mm rigid | 1.950 mm rigid +0.75 mm skin | 1.600 mm rigid +0.150 mm seat allowance +1.000 mm silicone |

These are identified line sections, not a global minimum-wall proof. The current verification includes exact XY/YZ locations and raw intervals. The side-wall reduction is deliberate allocation within the fixed finished envelope, away from the preserved critical rear and control lands. At the registration slots the remaining wall must also be reviewed with the actual process.

## Implemented changes retained or completed

1. **Selective silicone band:** nominal 1.00 mm normal thickness, bounded between Z3.8 and Z18.0, with radiused rigid PTT/volume/USB lands and a nominal 0.20 mm reveal. This eliminates the risky full rear and volume membranes without relocating electronics. Entire original rear material below the band is retained except the separately declared case counterbores.
2. **Serviceable attachment strategy:** four registration keys and a 0.15 mm nominal seat/bond allowance. A qualified bonded/serviceable silicone process is allowed; the model does not force a thin removable skin.
3. **USB:** deleted second-layer floor-lift patch; opened lower return ends; extended the central lower-film relief from the earlier Z4.90 limit to Z4.35. Measured lower-film clearance progresses from 0.0319 mm original tight floor, through 0.291752 mm first relief, to approximately 0.772688 mm. No PCB/receptacle movement or scaling.
4. **Actual acoustic opening:** 1153 through holes in the 46 ×46 ×0.50 R8 metal blank, Ø0.8 on 1.2 triangular pitch, with unperforated nominal 3.6 mm border. The old solid blank is not the finished grille.
5. **Backing and bond:** 42 ×42 R6 backing with a 0.18 mm spatial allocation; two separate vent-relieved 0.26 mm adhesive rings. The ring separation avoids adhesive spanning the 0.10 mm backing/rebate clearance. The separate speaker and microphone gaskets remain unchanged.
6. **Wire guides:** two integral 10 mm-wide guides at X54.2, Y54 and Y74, retaining the first pass’s useful routing provisions. Actual wire net assignments, conductor count and cut lengths remain outside geometric inference.
7. **Case fastening:** same four M2×12 screw shapes, translated +1.0 mm Z; rear bearing planes unified at Z2.8; forward tip relief Z15.3 gives nominal 0.5 mm tip reserve. Other hardware and mechanism references retain their supplied placements.
8. **Native CAD and interchange:** real FreeCAD document, ten named modules, linked parametric changed features and immutable reference bases. A stable native Boolean feature resolves the original back-shell Boolean failure. STEP exports omit stored p-curves to avoid the independently reproduced Back STEP wire defect. Round-trip comparisons use BREP and STEP measured consistently in a separate FreeCAD process; raw OCP export metrics are retained separately.
9. **Print meshes:** zero-area/duplicate tessellation faces are removed with recorded counts and without moving vertices or filling holes. Mesh checks are rerun. Old Bambu projects are not repackaged as new slicing evidence.

## What is deliberately not claimed

The installed silicone master is not shrink-compensated tooling or a rigid print. 30A is a design target; Dragon Skin 10NV is a separate 10A alternative. Supplier bend rating is unspecified; a 4 mm wire radius is a layout assumption. Neither general SLA accuracy nor nominal CAD gaps establish reliable tactile return, fit tolerance, adhesion, acoustic response, durability, ingress or powered electrical safety.