diff --git a/src/components/three/ModelViewer.tsx b/src/components/three/ModelViewer.tsx
index 9f5e75c..d6b8d6f 100644
--- a/src/components/three/ModelViewer.tsx
+++ b/src/components/three/ModelViewer.tsx
@@ -277,7 +277,7 @@ function GLBModel({ sceneModel, isActive }: { sceneModel: SceneModel; isActive:
           const wq = new THREE.Quaternion();
           (calGroupRef.current ?? e.object).getWorldQuaternion(wq);
           pushModelFaceNormal(n, wq);
-          if (calibration.step === 'done') {
+          if ((calibration.step as string) === 'done') {
             const q = computeCalibrationQuaternion(calibration.pairs);
             if (q) {
               useModelStore.getState().setCalibration(sceneModel.id, [q.x, q.y, q.z, q.w]);