STEP XY coordinates were converted to PCB layout coordinates by using the USB/grid-centered datum:
STEP datum X0 = 43.970 mm
STEP datum Y0 = 41.751 mm
PCB coordinate = STEP coordinate - datum
This keeps the USB-C opening centered at PCB X = 0 and aligns the extracted MX grid to a 19.05 mm pitch.
Board outline applied
Applied PCB outline: rounded rectangle, 89.0 mm × 83.6 mm, 3.0 mm corner radius.
This is a fit outline derived from the case/lid extents and slightly expanded from the first extracted pocket so the actual hotswap and encoder footprints are not clamped by the board boundary.
Routing remains deferred.
Mechanical anchor extraction
MX switch grid
The STEP geometry contains a regular MX-style 19.05 mm grid with nominal cutout centers:
Table
Column
STEP X (mm)
PCB X (mm)
C1
15.523
-28.447
C2
34.573
-9.397
C3
53.623
9.653
C4
72.673
28.703
Table
Row
STEP Y (mm)
PCB Y (mm)
Top
53.604
11.853
Middle
34.554
-7.197
Bottom
15.504
-26.247
Applied 11-key assignment
Updated per the user's reference photo: 3 switches on the top row, encoder at upper-right, then 4 switches on the middle row and 4 switches on the bottom row.
Table
Component
PCB X (mm)
PCB Y (mm)
SW1
-28.447
11.853
SW2
-9.397
11.853
SW3
9.653
11.853
SW4
-28.447
-7.197
SW5
-9.397
-7.197
SW6
9.653
-7.197
SW7
28.703
-7.197
SW8
-28.447
-26.247
SW9
-9.397
-26.247
SW10
9.653
-26.247
SW11
28.703
-26.247
The top-right MX cutout is left unpopulated because the encoder occupies the upper-right position in the reference layout.
Encoder
User-provided reference photo (2026-07-21) shows the encoder at the upper-right of the key cluster.
Right circular lid/case opening center extracted at approximately STEP (76.824, 68.351) mm.
Applied encoder position: ENC1 = (32.854, 26.600) mm.
USB-C
USB-C case opening extents include X ≈ 39.370 to 48.570 mm and Y ≈ 82.501 to 85.101 mm.
Opening center X ≈ 43.970 mm, aligned to PCB X = 0.
Applied J1 position: (0.000, 35.680) mm, rotation 180°, with the connector mouth toward the top edge.
Verification status
The exact requested mechanical anchors have been read back after mutation:
SW1–SW11 are on the STEP-derived MX grid in the 3+4+4 layout.
ENC1 is on the right circular encoder opening.
J1 is centered to the USB-C opening and rotated toward the top board edge.
No component-outside-board, component-body-overlap, overlapping-copper, or ground-return-loop checks are currently reported for the selected review set.
Airwires remain intentionally unresolved because routing is deferred until the mechanical placement is approved.
Open mechanical assumptions
The case provides a 4×3 MX grid but the electrical design has 11 switches plus one encoder. The current assignment intentionally leaves the top-right MX cutout unpopulated and uses the right circular opening for the encoder, matching the user's photo.
ENC1 uses a PEC11R/EC11-style substitute footprint. A final physical fit check against the actual encoder part and knob height is still required before manufacturing.