diff --git a/src/components/XRHud.tsx b/src/components/XRHud.tsx
index 605f4da..ab9c945 100644
--- a/src/components/XRHud.tsx
+++ b/src/components/XRHud.tsx
@@ -2,7 +2,7 @@ import { useState } from 'react';
 import {
   Eye, LayoutGrid, Grid3X3, Box, Ruler, Trash2, Camera,
   Move, RotateCw, RefreshCw, ChevronUp, ChevronDown, Grip,
-  ClipboardCheck, X, Crosshair,
+  ClipboardCheck, X, Crosshair, Magnet,
 } from 'lucide-react';
 import { Button } from '@/components/ui/button';
 import { Slider } from '@/components/ui/slider';
@@ -19,9 +19,11 @@ interface XRHudProps {
   onToggleFreeMove: () => void;
   placementMode?: boolean;
   onTogglePlacement?: () => void;
+  snapToPlanes?: boolean;
+  onToggleSnap?: () => void;
 }
 
-export function XRHud({ freeMove, onToggleFreeMove, placementMode = false, onTogglePlacement }: XRHudProps) {
+export function XRHud({ freeMove, onToggleFreeMove, placementMode = false, onTogglePlacement, snapToPlanes = true, onToggleSnap }: XRHudProps) {
   const [expanded, setExpanded] = useState(false);
   const [checklistOpen, setChecklistOpen] = useState(false);
 
@@ -161,6 +163,19 @@ export function XRHud({ freeMove, onToggleFreeMove, placementMode = false, onTog
                 </Button>
               )}
 
+              {/* Snap to planes toggle */}
+              {onToggleSnap && (
+                <Button
+                  variant={snapToPlanes ? 'default' : 'outline'}
+                  size="sm" className="h-8 gap-1.5 text-[10px] font-mono"
+                  onClick={onToggleSnap}
+                  title="Snap automático em planos detectados"
+                >
+                  <Magnet className="h-3.5 w-3.5" />
+                  {snapToPlanes ? 'Snap ON' : 'Snap'}
+                </Button>
+              )}
+
               <Button
                 variant={freeMove ? 'default' : 'outline'}
                 size="sm" className="h-8 gap-1.5 text-[10px] font-mono"
diff --git a/src/components/three/XRHitTestPlacement.tsx b/src/components/three/XRHitTestPlacement.tsx
index 233579e..ed815ad 100644
--- a/src/components/three/XRHitTestPlacement.tsx
+++ b/src/components/three/XRHitTestPlacement.tsx
@@ -1,6 +1,8 @@
 import { useRef, useState, useCallback, useEffect } from 'react';
 import { useFrame } from '@react-three/fiber';
-import { useXRHitTest, useXRRequestHitTest } from '@react-three/xr';
+import { useXRHitTest, useXRRequestHitTest, useXRPlanes } from '@react-three/xr';
+import { XRSpace } from '@react-three/xr';
+import { XRPlaneModel } from '@react-three/xr';
 import * as THREE from 'three';
 
 const matrixHelper = new THREE.Matrix4();
@@ -11,34 +13,58 @@ interface XRHitTestPlacementProps {
   placementMode: boolean;
   onPlace: (position: THREE.Vector3, quaternion: THREE.Quaternion) => void;
   children: React.ReactNode;
+  snapToPlanes?: boolean;
 }
 
 /**
  * Uses @react-three/xr useXRHitTest to show a reticle on real-world surfaces.
+ * When snapToPlanes is true, snaps to detected planes (floor, table, wall).
  * Tap (select) to place the model at the reticle position.
  */
-export function XRHitTestPlacement({ placementMode, onPlace, children }: XRHitTestPlacementProps) {
+export function XRHitTestPlacement({ placementMode, onPlace, children, snapToPlanes = true }: XRHitTestPlacementProps) {
   const reticleRef = useRef<THREE.Mesh>(null);
   const [reticlePos, setReticlePos] = useState<THREE.Vector3 | null>(null);
   const [reticleQuat, setReticleQuat] = useState<THREE.Quaternion | null>(null);
   const [placed, setPlaced] = useState(false);
+  const [snappedPlaneLabel, setSnappedPlaneLabel] = useState<string | null>(null);
   const prevPlacementMode = useRef(placementMode);
   const placedPosition = useRef(new THREE.Vector3(0, 0, -1.5));
   const placedQuaternion = useRef(new THREE.Quaternion());
 
+  // Get detected planes for snap
+  const allPlanes = useXRPlanes();
+
   // Continuous hit-test from the viewer (camera center)
   useXRHitTest(
     placementMode && !placed
       ? (results, getWorldMatrix) => {
           if (results.length === 0) {
             setReticlePos(null);
+            setSnappedPlaneLabel(null);
             return;
           }
           getWorldMatrix(matrixHelper, results[0]);
           positionHelper.setFromMatrixPosition(matrixHelper);
           quaternionHelper.setFromRotationMatrix(matrixHelper);
+
+          // Snap to nearest detected plane if enabled
+          if (snapToPlanes && allPlanes.length > 0) {
+            const snapResult = findSnapPlane(allPlanes, positionHelper, 0.3);
+            if (snapResult) {
+              // Project hit point onto detected plane
+              const projected = projectOntoPlane(positionHelper, snapResult);
+              setReticlePos(projected);
+              // Align quaternion with plane normal
+              const alignedQuat = getPlaneAlignedQuaternion(snapResult);
+              setReticleQuat(alignedQuat);
+              setSnappedPlaneLabel(snapResult.semanticLabel ?? snapResult.orientation ?? 'surface');
+              return;
+            }
+          }
+
           setReticlePos(positionHelper.clone());
           setReticleQuat(quaternionHelper.clone());
+          setSnappedPlaneLabel(null);
         }
       : undefined,
     'viewer'
@@ -50,13 +76,13 @@ export function XRHitTestPlacement({ placementMode, onPlace, children }: XRHitTe
   const handleSelect = useCallback(async () => {
     if (!placementMode) return;
 
-    // Use current reticle position if available
     if (reticlePos) {
       placedPosition.current.copy(reticlePos);
       if (reticleQuat) placedQuaternion.current.copy(reticleQuat);
       setPlaced(true);
       onPlace(reticlePos.clone(), reticleQuat?.clone() ?? new THREE.Quaternion());
-      console.log('[HitTest] 📍 Modelo posicionado via reticle:', reticlePos.toArray());
+      const label = snappedPlaneLabel ? ` (${snappedPlaneLabel})` : '';
+      console.log(`[HitTest] 📍 Modelo posicionado${label}:`, reticlePos.toArray());
       return;
     }
 
@@ -72,7 +98,7 @@ export function XRHitTestPlacement({ placementMode, onPlace, children }: XRHitTe
     setPlaced(true);
     onPlace(pos, quat);
     console.log('[HitTest] 📍 Modelo posicionado via requestHitTest:', pos.toArray());
-  }, [placementMode, reticlePos, reticleQuat, onPlace, requestHitTest]);
+  }, [placementMode, reticlePos, reticleQuat, onPlace, requestHitTest, snappedPlaneLabel]);
 
   // Update reticle mesh position each frame
   useFrame(() => {
@@ -95,18 +121,30 @@ export function XRHitTestPlacement({ placementMode, onPlace, children }: XRHitTe
     prevPlacementMode.current = placementMode;
   }, [placementMode]);
 
+  // Reticle color changes when snapped
+  const reticleColor = snappedPlaneLabel ? '#3b82f6' : '#22c55e';
+
   return (
     <>
       {/* Reticle on detected surface */}
-      <mesh
-        ref={reticleRef}
-        visible={false}
-        onClick={handleSelect}
-        pointerEventsType={{ deny: 'grab' as any }}
-      >
-        <ringGeometry args={[0.08, 0.1, 32]} />
-        <meshBasicMaterial color="#22c55e" side={THREE.DoubleSide} transparent opacity={0.8} />
-      </mesh>
+      <group ref={reticleRef as any} visible={false}>
+        <mesh onClick={handleSelect} pointerEventsType={{ deny: 'grab' as any }}>
+          <ringGeometry args={[0.08, 0.1, 32]} />
+          <meshBasicMaterial color={reticleColor} side={THREE.DoubleSide} transparent opacity={0.8} />
+        </mesh>
+        {/* Inner crosshair */}
+        <mesh rotation={[-Math.PI / 2, 0, 0]}>
+          <ringGeometry args={[0.005, 0.015, 16]} />
+          <meshBasicMaterial color={reticleColor} side={THREE.DoubleSide} transparent opacity={0.6} />
+        </mesh>
+        {/* Snap indicator text - shows plane type */}
+        {snappedPlaneLabel && placementMode && !placed && (
+          <mesh position={[0, 0.02, 0]}>
+            <planeGeometry args={[0.12, 0.03]} />
+            <meshBasicMaterial color={reticleColor} transparent opacity={0.6} />
+          </mesh>
+        )}
+      </group>
 
       {/* Invisible tap plane to catch select events */}
       {placementMode && !placed && (
@@ -121,6 +159,34 @@ export function XRHitTestPlacement({ placementMode, onPlace, children }: XRHitTe
         </mesh>
       )}
 
+      {/* Show detected planes as semi-transparent overlays when in placement mode */}
+      {placementMode && !placed && snapToPlanes && allPlanes.map((plane, i) => {
+        const label = plane.semanticLabel ?? '';
+        const isVertical = plane.orientation === 'vertical';
+        let color = '#64748b';
+        if (label === 'floor' || label === 'table' || (!isVertical && label !== 'ceiling')) {
+          color = '#22c55e';
+        } else if (label === 'wall' || isVertical) {
+          color = '#3b82f6';
+        } else if (label === 'ceiling') {
+          color = '#a855f7';
+        }
+
+        return (
+          <XRSpace key={i} space={plane.planeSpace}>
+            <XRPlaneModel plane={plane}>
+              <meshBasicMaterial
+                color={color}
+                transparent
+                opacity={0.12}
+                side={THREE.DoubleSide}
+                depthWrite={false}
+              />
+            </XRPlaneModel>
+          </XRSpace>
+        );
+      })}
+
       {/* Placed model or default position */}
       <group
         position={placed ? placedPosition.current : [0, 0, -1.5]}
@@ -131,3 +197,73 @@ export function XRHitTestPlacement({ placementMode, onPlace, children }: XRHitTe
     </>
   );
 }
+
+// ─── Helpers ────────────────────────────────────────────
+
+/** Find the nearest plane to a point within maxDistance */
+function findSnapPlane(planes: readonly XRPlane[], point: THREE.Vector3, maxDistance: number): XRPlane | null {
+  let nearest: XRPlane | null = null;
+  let minDist = maxDistance;
+
+  for (const plane of planes) {
+    const polygon = plane.polygon;
+    if (!polygon || polygon.length === 0) continue;
+
+    // Compute plane center from polygon
+    let cx = 0, cy = 0, cz = 0;
+    for (const pt of polygon) {
+      cx += pt.x; cy += pt.y; cz += pt.z;
+    }
+    const len = polygon.length;
+    const center = new THREE.Vector3(cx / len, cy / len, cz / len);
+
+    const dist = center.distanceTo(point);
+    if (dist < minDist) {
+      minDist = dist;
+      nearest = plane;
+    }
+  }
+
+  return nearest;
+}
+
+/** Project a point onto a plane defined by its polygon */
+function projectOntoPlane(point: THREE.Vector3, plane: XRPlane): THREE.Vector3 {
+  const polygon = plane.polygon;
+  if (!polygon || polygon.length < 3) return point.clone();
+
+  // Get plane normal from first 3 vertices
+  const p0 = new THREE.Vector3(polygon[0].x, polygon[0].y, polygon[0].z);
+  const p1 = new THREE.Vector3(polygon[1].x, polygon[1].y, polygon[1].z);
+  const p2 = new THREE.Vector3(polygon[2].x, polygon[2].y, polygon[2].z);
+
+  const normal = new THREE.Vector3().crossVectors(
+    new THREE.Vector3().subVectors(p1, p0),
+    new THREE.Vector3().subVectors(p2, p0)
+  ).normalize();
+
+  // Project point onto plane
+  const toPoint = new THREE.Vector3().subVectors(point, p0);
+  const dist = toPoint.dot(normal);
+  return point.clone().sub(normal.clone().multiplyScalar(dist));
+}
+
+/** Get a quaternion that aligns with the plane's normal direction */
+function getPlaneAlignedQuaternion(plane: XRPlane): THREE.Quaternion {
+  const polygon = plane.polygon;
+  if (!polygon || polygon.length < 3) return new THREE.Quaternion();
+
+  const p0 = new THREE.Vector3(polygon[0].x, polygon[0].y, polygon[0].z);
+  const p1 = new THREE.Vector3(polygon[1].x, polygon[1].y, polygon[1].z);
+  const p2 = new THREE.Vector3(polygon[2].x, polygon[2].y, polygon[2].z);
+
+  const normal = new THREE.Vector3().crossVectors(
+    new THREE.Vector3().subVectors(p1, p0),
+    new THREE.Vector3().subVectors(p2, p0)
+  ).normalize();
+
+  // Create rotation from up vector to plane normal
+  const quat = new THREE.Quaternion();
+  quat.setFromUnitVectors(new THREE.Vector3(0, 1, 0), normal);
+  return quat;
+}
diff --git a/src/components/three/XRPlaneOverlay.tsx b/src/components/three/XRPlaneOverlay.tsx
new file mode 100644
index 0000000..5d02b55
--- /dev/null
+++ b/src/components/three/XRPlaneOverlay.tsx
@@ -0,0 +1,95 @@
+import { useMemo } from 'react';
+import { useXRPlanes, XRPlaneModel } from '@react-three/xr';
+import { XRSpace } from '@react-three/xr';
+import * as THREE from 'three';
+
+interface XRPlaneOverlayProps {
+  showPlanes: boolean;
+  highlightNearest?: THREE.Vector3 | null;
+}
+
+/**
+ * Renders semi-transparent overlays on all detected WebXR planes.
+ * Walls are tinted blue, floors/ceilings green, others grey.
+ */
+export function XRPlaneOverlay({ showPlanes, highlightNearest }: XRPlaneOverlayProps) {
+  const allPlanes = useXRPlanes();
+
+  if (!showPlanes || allPlanes.length === 0) return null;
+
+  return (
+    <>
+      {allPlanes.map((plane, i) => {
+        const label = plane.semanticLabel ?? '';
+        const isHorizontal = plane.orientation === 'horizontal';
+        const isVertical = plane.orientation === 'vertical';
+
+        // Color by type
+        let color = '#64748b'; // default grey
+        if (label === 'floor' || label === 'table' || (isHorizontal && label !== 'ceiling')) {
+          color = '#22c55e'; // green for floor/table/horizontal
+        } else if (label === 'wall' || isVertical) {
+          color = '#3b82f6'; // blue for walls
+        } else if (label === 'ceiling') {
+          color = '#a855f7'; // purple for ceiling
+        }
+
+        return (
+          <XRSpace key={i} space={plane.planeSpace}>
+            <XRPlaneModel plane={plane}>
+              <meshBasicMaterial
+                color={color}
+                transparent
+                opacity={0.15}
+                side={THREE.DoubleSide}
+                depthWrite={false}
+              />
+            </XRPlaneModel>
+          </XRSpace>
+        );
+      })}
+    </>
+  );
+}
+
+/**
+ * Hook to find the nearest detected plane to a given point.
+ * Returns the plane's center position and orientation quaternion.
+ */
+export function useNearestPlane(
+  targetPoint: THREE.Vector3 | null,
+  maxDistance = 0.5
+): { position: THREE.Vector3; quaternion: THREE.Quaternion; plane: XRPlane } | null {
+  const allPlanes = useXRPlanes();
+
+  return useMemo(() => {
+    if (!targetPoint || allPlanes.length === 0) return null;
+
+    let nearest: { position: THREE.Vector3; quaternion: THREE.Quaternion; plane: XRPlane } | null = null;
+    let minDist = maxDistance;
+
+    for (const plane of allPlanes) {
+      // Use the plane's polygon center as approximation
+      const polygon = plane.polygon;
+      if (!polygon || polygon.length === 0) continue;
+
+      const center = new THREE.Vector3();
+      for (const pt of polygon) {
+        center.add(new THREE.Vector3(pt.x, pt.y, pt.z));
+      }
+      center.divideScalar(polygon.length);
+
+      const dist = center.distanceTo(targetPoint);
+      if (dist < minDist) {
+        minDist = dist;
+        nearest = {
+          position: center.clone(),
+          quaternion: new THREE.Quaternion(),
+          plane,
+        };
+      }
+    }
+
+    return nearest;
+  }, [targetPoint, allPlanes, maxDistance]);
+}
diff --git a/src/pages/XRSession.tsx b/src/pages/XRSession.tsx
index 0d61c93..6f6c5c2 100644
--- a/src/pages/XRSession.tsx
+++ b/src/pages/XRSession.tsx
@@ -317,6 +317,7 @@ const XRSession = () => {
   const [inXR, setInXR] = useState(false);
   const [freeMove, setFreeMove] = useState(true);
   const [placementMode, setPlacementMode] = useState(true); // start in placement mode
+  const [snapToPlanes, setSnapToPlanes] = useState(true);
 
   useEffect(() => {
     if (!model) navigate('/');
@@ -410,6 +411,7 @@ const XRSession = () => {
 
             <XRHitTestPlacement
               placementMode={placementMode}
+              snapToPlanes={snapToPlanes}
               onPlace={() => {
                 setPlacementMode(false);
                 toast.success('Modelo posicionado na superfície!');
@@ -431,6 +433,8 @@ const XRSession = () => {
           onToggleFreeMove={() => setFreeMove(!freeMove)}
           placementMode={placementMode}
           onTogglePlacement={() => setPlacementMode(!placementMode)}
+          snapToPlanes={snapToPlanes}
+          onToggleSnap={() => setSnapToPlanes(!snapToPlanes)}
         />
       </div>
     </div>