Fuse multiple objects at once (#659)

* Consider multiple selection

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Can fuse multiple objects now

* cleanup

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

packages/base/src/commands.ts

@@ -345,13 +345,19 @@ const OPERATORS = {
     default: (model: IJupyterCadModel) => {
       const objects = model.getAllObject();
       const selected = model.localState?.selected.value || {};
-      const sel0 = getSelectedMeshName(selected, 0);
-      const sel1 = getSelectedMeshName(selected, 1);
-      const baseName = sel0 || objects[0].name || '';
-      const baseModel = model.sharedModel.getObjectByName(baseName);
+
+      const selectedShapes = Object.keys(selected).map(key => key);
+
+      // Fallback to at least two objects if selection is empty
+      const baseShapes =
+        selectedShapes.length > 0
+          ? selectedShapes
+          : [objects[0].name || '', objects[1].name || ''];
+
+      const baseModel = model.sharedModel.getObjectByName(baseShapes[0]);
       return {
         Name: newName('Union', model),
-        Shapes: [baseName, sel1 || objects[1].name || ''],
+        Shapes: baseShapes,
         Refine: false,
         Color: baseModel?.parameters?.Color || DEFAULT_MESH_COLOR,
         Placement: { Position: [0, 0, 0], Axis: [0, 0, 1], Angle: 0 }

packages/occ-worker/src/occapi/fuse.ts

@@ -30,13 +30,27 @@ export function _Fuse(
       }
     }
   });
-  const operator = new oc.BRepAlgoAPI_Fuse_3(
-    occShapes[0],
-    occShapes[1],
-    new oc.Message_ProgressRange_1()
-  );
-  if (operator.IsDone()) {
-    return setShapePlacement(operator.Shape(), Placement);
+
+  if (occShapes.length === 0) {
+    return;
+  }
+
+  let fusedShape = occShapes[0];
+
+  for (let i = 1; i < occShapes.length; i++) {
+    const operator = new oc.BRepAlgoAPI_Fuse_3(
+      fusedShape,
+      occShapes[i],
+      new oc.Message_ProgressRange_1()
+    );
+
+    if (operator.IsDone()) {
+      fusedShape = operator.Shape();
+    } else {
+      console.error(`Fusion failed at index ${i}`);
+      return;
+    }
   }
-  return;
+
+  return setShapePlacement(fusedShape, Placement);
 }