diff --git a/src/components/XRHud.tsx b/src/components/XRHud.tsx
index 9b88bb1..8817686 100644
--- a/src/components/XRHud.tsx
+++ b/src/components/XRHud.tsx
@@ -312,6 +312,22 @@ export function XRHud({ freeMove, onToggleFreeMove, placementMode = false, onTog
                 </Button>
               )}
 
+              {/* Lock / Unlock — fixa a peça no espaço */}
+              <Button
+                variant={isLocked ? 'default' : 'outline'}
+                size="sm" className="h-8 gap-1.5 text-[10px] font-mono"
+                onClick={() => {
+                  const next = !isLocked;
+                  setLocked(next);
+                  console.log(`[lock] ${next ? 'ON' : 'OFF'}`);
+                  toast[next ? 'success' : 'message'](next ? 'Peça fixada no espaço 🔒' : 'Peça liberada 🔓');
+                }}
+                title="Fixa/libera a peça no espaço (ignora Grip enquanto travada)"
+              >
+                {isLocked ? <Lock className="h-3.5 w-3.5" /> : <Unlock className="h-3.5 w-3.5" />}
+                {isLocked ? 'Fixada' : 'Fixar'}
+              </Button>
+
               <Button
                 variant={freeMove ? 'default' : 'outline'}
                 size="sm" className="h-8 gap-1.5 text-[10px] font-mono"