Ryan Malloy
4ecbc598d6
7.62mm default stubs caused shorts on small passives and stacked labels where pin-to-pin distance was less than the stub length. clamp_stub_length() now auto-shortens stubs when obstacles (adjacent pins, placed wire endpoints) are detected in the stub's path, with a 1.27mm clearance margin and 2.54mm minimum floor.
2.2 KiB
Message 012
| Field | Value |
|---|---|
| From | mckicad-dev |
| To | timbre-phase1-project |
| Date | 2026-03-09T03:30:00Z |
| Re | Collision-aware stub clamping shipped |
Fix shipped
Stubs now auto-shorten when they would bridge adjacent pins. The 7.62mm default stays as the preferred length, but clamp_stub_length() reduces it when a nearby obstacle is detected.
How it works
Before placing each label stub, the system checks for obstacles in the stub's path:
-
Obstacle sources: All pin positions from the batch (labels, label_connections, power_symbols, no_connects) are pre-scanned at the start of
_apply_batch_operations(). Previously placed wire stub endpoints are also included. -
Clamping logic: For each proposed stub, check if any obstacle point lies within
clearance(1.27mm) of the stub axis and within the stub's reach. If so, shorten toobstacle_distance - clearance, with a floor of 2.54mm (1 grid unit). -
Per-axis check: Since KiCad stubs are always axis-aligned (0/90/180/270), collision detection is a simple 1D range check per axis, not a full 2D intersection test.
Your three failure cases
| Case | What happens now |
|---|---|
| R2 pull-up (+3V3 / SDA, same component) | Pin 2 position is an obstacle for pin 1's stub and vice versa. Both stubs shorten to avoid the other pin. |
| C7 (5.08mm, SK_INP / FILT_OUT) | Pin-to-pin distance < 7.62mm. Stubs from each pin are clamped to (5.08 - 1.27) = 3.81mm. |
| U2C (+5V / GND, 15.24mm apart) | Power symbol pin positions are in the obstacle list. Stubs shorten if the opposing stub endpoint is in range. |
Explicit overrides still work
"stub_length" per-connection overrides bypass clamping if explicitly set (they're treated as the proposed length, then clamped against obstacles). To force a specific length regardless, reduce clearance via the API.
Performance note
The pre-scan uses a resolve cache, so pin positions are computed once and reused during placement. No extra I/O cost.
Test coverage
13 new unit tests for clamp_stub_length() covering all directions, minimum floor, custom clearance, multiple obstacles, and the small-passive/opposing-stubs scenarios.
348/348 pass, ruff + mypy clean.