diff --git a/src/stores/useModelStore.ts b/src/stores/useModelStore.ts
index 2a4b883..9d24072 100644
--- a/src/stores/useModelStore.ts
+++ b/src/stores/useModelStore.ts
@@ -118,6 +118,10 @@ interface ModelStore {
   addScreenshot: (dataUrl: string) => void;
   removeScreenshot: (index: number) => void;
   clearScreenshots: () => void;
+
+  /** When true, the grabbed model stays frozen in world space (grip is ignored). */
+  isLocked: boolean;
+  setLocked: (locked: boolean) => void;
 }
 
 const defaultFineTuning: FineTuning = { posX: 0, posY: 0, posZ: 0, rotX: 0, rotY: 0, rotZ: 0, scale: 1 };