# Release identity and verification - 28.1 / R3.4

Website version **28.1** = engineering **R3.4 Print Prototype**, prepared 14 September 2026. R3.4 filenames are intentional. This is the R3.3-derived branch; keep it separate from 28.2 and earlier R3.2 A files.

Website label 28.1 is an alias for this engineering R3.4 checkpoint. It replaces the default page's older R3.2 A presentation; the archived R3.2 A and frozen 28 / R3.1 files retain their identity. Never overwrite this checkpoint for a later geometry change.

## Exact CAD identities

| File | Bytes | SHA-256 |
| --- | --- | --- |
| Walkie_One_28_R3_4_REFERENCE_ASSEMBLY_NOT_FOR_SLICER.step | 31917506 | 8225c7b494a1dba6cc91e7251539007268a1fd52d0bb531302c7296d3b7adaa0 |
| Walkie_One_28_R3_4_FULL_REFERENCE_ASSEMBLY.f3d | 13912839 | 2c5612e4c54e99848faf538302d4e6fdd5e545e00beadd109f1b21d2f27bcdec |
| Walkie_One_28_R3_4_PRINT_PARTS_ONLY.f3d | 1620509 | af1ffe2647937bab7a2286f0a804b7e841b43ec5644ba8f0ce690227339aeba0 |

## Completed digital checks

- All 25 individual STEP parts are valid single solids. All 25 individual STL files are single watertight meshes.
- The structural wall screen used 225,102 sample starts; no accepted structural thickness below 1 mm was flagged. This is sampled geometric evidence, not a universal tolerance certification.
- Twenty discrete nominal button positions have no unintended intersection in the checked motion study. They do not establish real switch force, electrical release or spring return.
- Local printed-part and reserved cable/terminal clearance checks recorded no new flagged conflicts. These are narrower than the unresolved complete-harness assessment inherited from R3.3.
- Full-reference and print-only native archives were reopened and the 25 committed print bodies verified. Zero-volume planar keeper sheets were removed before final export; material shape was preserved.
- All five Bambu Studio 2.7.1.62 projects were test-sliced: every intended part included, inside the plate, zero mesh-repair counters. Editable projects require slicing for the selected filament and bed.

## Files to choose

The full STEP/F3D is for assembly and component review. The print-only F3D and 25 current individual STEP/STLs define the printable design. Four main P1S projects contain 21 rigid parts; optional plate 05 has two opaque optical proxies. Two flexible STLs require another material/profile. Do not send the working-baseline F3D or interim trial geometry as this release.

## Boundaries still open

- **Controls:** Measure switch body/terminals, free/operating height, travel and force. Confirm electrical continuity/contact pair, free return at PTT ends and release with case closed.
- **PCB and U6:** Supplied populated STEP omits U6 solid. Current 24 x 24 x 2.4 mm placeholder supports preliminary clearance only; check corrected populated STEP or physical board, connectors and heights.
- **Full harness:** R3.3 tested J2 CK reservations and both stock-PH adapter poses conflict; all 12 tested J3/J10 local bend patterns conflict. No complete closed-case harness, common-return branch route or cover-opening slack is validated.
- **Battery and USB:** Measure actual pack/tape/lead envelope, establish pad behavior and no-pressure retention, verify USB plug seating and approach with the chosen cable. Nominal dimensions are not maximum tolerances.
- **Fasteners:** Confirm actual head geometry, blind depth, engagement, tapping/fastening method and torque on sacrificial prints; inspect screw tips near battery, wires and controls.
- **Optics, sound and RF:** Use functional optical material, real mesh/seals and antenna. Validate light output, sound, cellular RF, thermal behavior and durability after assembly.
- **Finish / process:** Approve actual resin/elastomer or finish samples with RPS. Printed simplifications and integrated caps do not automatically constitute a urethane-casting or metal-machining release.

## Evidence basis

Current geometry: R3_4_Print_Simplification/audit/committed_inventory.json, independent_part_export_verification.json, native_thickness/parts/*.json, native_motion_samples.json, final_changes.json, final_surface_cleanup.json, reopened_native_verification.json, reopened_print_only.json, exported_archive_hashes.json, and print_ready/slice_checks/final_verification.json.

Inherited parts/materials: R3.3 prepared-package Materials_and_Colour_Targets.md, CHANGELOG_BOM_AND_OPEN_GATES.md, HARNESS_BOUNDARY_AND_WIRING_SCHEDULE.md and owner PARTS record. Pantone names, libraries and URLs are carried from corrected R3.1 DOC C1. The 18 original fastener references come from R3.1 Assembly_and_Nonprinted_Parts.md; current +2/+4 guide/battery references are verified against R3.4 final changes and preserved-reference inventory. Source SHA-256 values are recorded in documents_manifest.json.