diff --git a/src/stores/useModelStore.ts b/src/stores/useModelStore.ts
index b34919e..8fb4c1a 100644
--- a/src/stores/useModelStore.ts
+++ b/src/stores/useModelStore.ts
@@ -379,6 +379,25 @@ export const useModelStore = create<ModelStore>((set, get) => ({
 
   scaleRatio: SCALE_PRESETS.find(p => p.label === '1:1')!,
   setScaleRatio: (scaleRatio) => set({ scaleRatio }),
+  scaleResetNonce: 0,
+  resetScale: () => set((state) => {
+    const oneToOne = SCALE_PRESETS.find(p => p.label === '1:1')!;
+    const activeId = state.activeModelId;
+    const models = activeId
+      ? state.models.map(m => m.id === activeId
+          ? { ...m, fineTuning: { ...m.fineTuning, scale: 1 } }
+          : m)
+      : state.models;
+    const active = models.find(m => m.id === activeId);
+    const fineTuning = active ? { ...active.fineTuning } : { ...state.fineTuning, scale: 1 };
+    if (active) savePlacement(active.fileName, fineTuning);
+    return {
+      scaleRatio: oneToOne,
+      models,
+      fineTuning,
+      scaleResetNonce: state.scaleResetNonce + 1,
+    };
+  }),
 
   opacity: 1,
   setOpacity: (opacity) => set({ opacity }),