fix: sot343 symmetric about origin, matching KiCad SOT-343_SC-70-4

src/fn/sot343.ts

@@ -8,19 +8,21 @@ import { z } from "zod"
 import { rectpad } from "../helpers/rectpad"
 import { base_def } from "../helpers/zod/base_def"
 
+// Matches KiCad Package_TO_SOT_SMD.pretty SOT-343_SC-70-4 exactly
+// (outer edge +/-1.45, inner arms +/-0.73, y +/-0.98 with +/-1.1 tabs).
 const sot343CourtyardOutline = [
-  { x: -1.703, y: 0.98 },
-  { x: -0.983, y: 0.98 },
-  { x: -0.983, y: 1.1 },
-  { x: 0.477, y: 1.1 },
-  { x: 0.477, y: 0.98 },
-  { x: 1.197, y: 0.98 },
-  { x: 1.197, y: -0.98 },
-  { x: 0.477, y: -0.98 },
-  { x: 0.477, y: -1.1 },
-  { x: -0.983, y: -1.1 },
-  { x: -0.983, y: -0.98 },
-  { x: -1.703, y: -0.98 },
+  { x: -1.45, y: 0.98 },
+  { x: -0.73, y: 0.98 },
+  { x: -0.73, y: 1.1 },
+  { x: 0.73, y: 1.1 },
+  { x: 0.73, y: 0.98 },
+  { x: 1.45, y: 0.98 },
+  { x: 1.45, y: -0.98 },
+  { x: 0.73, y: -0.98 },
+  { x: 0.73, y: -1.1 },
+  { x: -0.73, y: -1.1 },
+  { x: -0.73, y: -0.98 },
+  { x: -1.45, y: -0.98 },
 ]
 
 export const sot343_def = base_def.extend({
@@ -64,10 +66,17 @@ export const getCcwSot343Coords = (parameters: {
   p: number
 }) => {
   const { pn, p } = parameters
-  if (pn === 1) return { x: -p * 1.92, y: -0.65 }
-  if (pn === 2) return { x: -p * 1.92, y: 0.65 }
-  if (pn === 3) return { x: p, y: 0.65 }
-  if (pn === 4) return { x: p, y: -0.65 }
+  // SC-70-4 (SOT-343) is symmetric about the origin: both columns sit at
+  // ±p*1.92 from centre. The right column previously dropped the *1.92,
+  // shifting the part off origin (#667).
+  // SC-70-4 (SOT-343) is symmetric about the origin. KiCad's
+  // SOT-343_SC-70-4 places pads at +/-0.825mm (p*1.5 with the default
+  // 0.55mm pitch); the old code put the right column at +p*1 only and
+  // the left at -p*1.92, shifting the part off origin (#667).
+  if (pn === 1) return { x: -p * 1.5, y: -0.65 }
+  if (pn === 2) return { x: -p * 1.5, y: 0.65 }
+  if (pn === 3) return { x: p * 1.5, y: 0.65 }
+  if (pn === 4) return { x: p * 1.5, y: -0.65 }
   return { x: 0, y: 0 }
 }