diff --git a/src/components/three/XRHudInWorld.tsx b/src/components/three/XRHudInWorld.tsx
index 182ff60..c44c282 100644
--- a/src/components/three/XRHudInWorld.tsx
+++ b/src/components/three/XRHudInWorld.tsx
@@ -392,6 +392,14 @@ function ToolsTab(p: XRHudInWorldProps) {
         label="✕ Medidas" color="#dc2626"
         onClick={clearMeasurements} fontSize={0.0085} />
 
+      {/* Legenda dos controles para Medir */}
+      {measureMode && (
+        <Text position={[-0.24, -0.145, 0]} fontSize={0.0065} color="#a3e635" anchorX="left" maxWidth={0.5}>
+          Gatilho D: marcar · A: desfazer · B: limpar · Gatilho E: alternar snap
+        </Text>
+      )}
+
+
       {/* Grid floor controls */}
       <GridFloorRow />
     </group>