Fallback to pcb_component rectangles when mesh boxes are missing

lib/mesh-generation.ts

@@ -43,6 +43,7 @@ export async function generateComponentMeshes(
   } = options
 
   const solids: GeneratedSceneSolid[] = []
+  let fallbackCircuitJson = circuitJson
 
   try {
     const filteredCircuitJson = circuitJson
@@ -93,6 +94,7 @@ export async function generateComponentMeshes(
 
         return element
       })
+    fallbackCircuitJson = filteredCircuitJson as CircuitJson
 
     const { convertCircuitJsonTo3D } = await getCircuitJsonToGltfModule()
 
@@ -101,12 +103,83 @@ export async function generateComponentMeshes(
       renderBoardTextures: false,
     })
 
-    for (const box of scene3d.boxes as SceneBox[]) {
+    const boxes = scene3d.boxes?.length
+      ? (scene3d.boxes as SceneBox[])
+      : createFallbackComponentBoxes(filteredCircuitJson, boardThickness)
+
+    for (const box of boxes) {
       solids.push(createSceneBoxSolid(repo, box))
     }
   } catch (error) {
     console.warn("Failed to generate component mesh:", error)
+    for (const box of createFallbackComponentBoxes(
+      fallbackCircuitJson,
+      boardThickness,
+    )) {
+      solids.push(createSceneBoxSolid(repo, box))
+    }
   }
 
   return solids
 }
+
+export function createFallbackComponentBoxes(
+  circuitJson: CircuitJson,
+  boardThickness: number,
+): SceneBox[] {
+  const sourceNames = new Map<string, string>()
+  for (const element of circuitJson as any[]) {
+    if (
+      element.type === "source_component" &&
+      element.source_component_id &&
+      element.name
+    ) {
+      sourceNames.set(element.source_component_id, element.name)
+    }
+  }
+
+  const componentThickness = 0.6
+
+  return (circuitJson as any[])
+    .filter((element) => element.type === "pcb_component")
+    .map((component): SceneBox | null => {
+      const center = component.center
+      const centerX = Number(center?.x)
+      const centerY = Number(center?.y)
+      const width = Number(component.width)
+      const height = Number(component.height)
+      if (
+        !Number.isFinite(centerX) ||
+        !Number.isFinite(centerY) ||
+        !Number.isFinite(width) ||
+        !Number.isFinite(height)
+      ) {
+        return null
+      }
+
+      const layer = component.layer === "bottom" ? "bottom" : "top"
+      const verticalSign = layer === "bottom" ? -1 : 1
+      const rotationDegrees = Number(component.rotation ?? 0)
+
+      return {
+        center: {
+          x: centerX,
+          y: verticalSign * (boardThickness / 2 + componentThickness / 2),
+          z: centerY,
+        },
+        size: {
+          x: width,
+          y: componentThickness,
+          z: height,
+        },
+        rotation: Number.isFinite(rotationDegrees)
+          ? { x: 0, y: (-rotationDegrees * Math.PI) / 180, z: 0 }
+          : undefined,
+        label:
+          sourceNames.get(component.source_component_id) ??
+          component.pcb_component_id ??
+          "Component",
+      }
+    })
+    .filter((box): box is SceneBox => box !== null)
+}

test/fallback-component-boxes.test.ts

@@ -0,0 +1,67 @@
+import { expect, test } from "bun:test"
+
+import { createFallbackComponentBoxes } from "../lib/mesh-generation"
+
+test("creates fallback STEP boxes from pcb_component rectangles", () => {
+  const boxes = createFallbackComponentBoxes(
+    [
+      {
+        type: "source_component",
+        source_component_id: "source_component_1",
+        name: "R1",
+        supplier_part_numbers: {},
+        ftype: "simple_resistor",
+      },
+      {
+        type: "pcb_component",
+        pcb_component_id: "pcb_component_1",
+        source_component_id: "source_component_1",
+        center: { x: 12, y: 7 },
+        width: 3.2,
+        height: 1.6,
+        layer: "top",
+        rotation: 90,
+      },
+      {
+        type: "pcb_component",
+        pcb_component_id: "pcb_component_2",
+        center: { x: -4, y: 2 },
+        width: 2,
+        height: 1.25,
+        layer: "bottom",
+      },
+    ] as any,
+    1.6,
+  )
+
+  expect(boxes).toHaveLength(2)
+  expect(boxes[0]).toMatchObject({
+    center: { x: 12, y: 1.1, z: 7 },
+    size: { x: 3.2, y: 0.6, z: 1.6 },
+    label: "R1",
+  })
+  expect(boxes[0]!.rotation?.y).toBeCloseTo(-Math.PI / 2)
+
+  expect(boxes[1]).toMatchObject({
+    center: { x: -4, y: -1.1, z: 2 },
+    size: { x: 2, y: 0.6, z: 1.25 },
+    label: "pcb_component_2",
+  })
+})
+
+test("skips fallback component boxes with missing dimensions", () => {
+  const boxes = createFallbackComponentBoxes(
+    [
+      {
+        type: "pcb_component",
+        pcb_component_id: "missing_width",
+        center: { x: 0, y: 0 },
+        height: 1,
+        layer: "top",
+      },
+    ] as any,
+    1.6,
+  )
+
+  expect(boxes).toHaveLength(0)
+})