diff --git a/src/rendering/water-material.ts b/src/rendering/water-material.ts
index 4aa52aad..84f67413 100644
--- a/src/rendering/water-material.ts
+++ b/src/rendering/water-material.ts
@@ -100,7 +100,7 @@ function createInverseVolumeRotation(rotationDegrees: Vec3) {
     .invert();
 }
 
-export function collectWaterContactPatches(volume: OrientedWaterVolume, contactBounds: WaterContactBounds[]): WaterContactPatch[] {
+export function collectWaterContactPatches(volume: OrientedWaterVolume, contactBounds: WaterContactSource[]): WaterContactPatch[] {
   const inverseRotation = createInverseVolumeRotation(volume.rotationDegrees);
   const halfX = Math.max(volume.size.x * 0.5, WATER_CONTACT_EPSILON);
   const halfY = Math.max(volume.size.y * 0.5, WATER_CONTACT_EPSILON);
diff --git a/src/runtime-three/runtime-host.ts b/src/runtime-three/runtime-host.ts
index c4a03e57..1eaa90e4 100644
--- a/src/runtime-three/runtime-host.ts
+++ b/src/runtime-three/runtime-host.ts
@@ -38,7 +38,7 @@ import {
   resolveBoxVolumeRenderPaths,
   type ResolvedBoxVolumeRenderPaths
 } from "../rendering/advanced-rendering";
-import { collectWaterContactPatches, createWaterContactPatchUniformValue, createWaterMaterial } from "../rendering/water-material";
+import { collectWaterContactPatches, createWaterContactPatchAxisUniformValue, createWaterContactPatchUniformValue, createWaterMaterial } from "../rendering/water-material";
 import {
   areAdvancedRenderingSettingsEqual,
   cloneAdvancedRenderingSettings,
@@ -71,6 +71,7 @@ interface LocalLightRenderObjects {
 interface RuntimeWaterContactUniformBinding {
   brush: RuntimeBoxBrushInstance;
   uniform: { value: import("three").Vector4[] };
+  axisUniform: { value: import("three").Vector2[] };
   staticContactPatches: ReturnType<typeof collectWaterContactPatches>;
 }
 
@@ -631,10 +632,11 @@ export class RuntimeHost {
         this.volumeAnimatedUniforms.push(waterMaterial.animationUniform);
       }
 
-      if (faceId === "posY" && waterMaterial.contactPatchesUniform !== null) {
+      if (faceId === "posY" && waterMaterial.contactPatchesUniform !== null && waterMaterial.contactPatchAxesUniform !== null) {
         this.runtimeWaterContactUniforms.push({
           brush,
           uniform: waterMaterial.contactPatchesUniform,
+          axisUniform: waterMaterial.contactPatchAxesUniform,
           staticContactPatches
         });
       }
@@ -811,10 +813,31 @@ export class RuntimeHost {
   }
 
   private collectRuntimeStaticWaterContactPatches(brush: RuntimeBoxBrushInstance) {
-    const contactBounds = this.runtimeScene?.colliders.map((collider) => ({
-      min: collider.worldBounds.min,
-      max: collider.worldBounds.max
-    })) ?? [];
+    const contactBounds: Parameters<typeof collectWaterContactPatches>[1] = [];
+
+    for (const otherBrush of this.runtimeScene?.brushes ?? []) {
+      if (otherBrush.id === brush.id || otherBrush.volume.mode !== "none") {
+        continue;
+      }
+
+      contactBounds.push({
+        kind: "orientedBox",
+        center: otherBrush.center,
+        rotationDegrees: otherBrush.rotationDegrees,
+        size: otherBrush.size
+      });
+    }
+
+    for (const collider of this.runtimeScene?.colliders ?? []) {
+      if (collider.source !== "modelInstance") {
+        continue;
+      }
+
+      contactBounds.push({
+        min: collider.worldBounds.min,
+        max: collider.worldBounds.max
+      });
+    }
 
     return collectWaterContactPatches(
       {
@@ -852,9 +875,9 @@ export class RuntimeHost {
 
   private updateRuntimeWaterContactUniforms() {
     for (const binding of this.runtimeWaterContactUniforms) {
-      binding.uniform.value = createWaterContactPatchUniformValue(
-        this.mergeRuntimeWaterContactPatches(binding.staticContactPatches, this.collectRuntimePlayerWaterContactPatches(binding.brush))
-      );
+      const mergedPatches = this.mergeRuntimeWaterContactPatches(binding.staticContactPatches, this.collectRuntimePlayerWaterContactPatches(binding.brush));
+      binding.uniform.value = createWaterContactPatchUniformValue(mergedPatches);
+      binding.axisUniform.value = createWaterContactPatchAxisUniformValue(mergedPatches);
     }
   }
 
diff --git a/src/viewport-three/viewport-host.ts b/src/viewport-three/viewport-host.ts
index b3089ba5..147cc29b 100644
--- a/src/viewport-three/viewport-host.ts
+++ b/src/viewport-three/viewport-host.ts
@@ -3007,14 +3007,19 @@ export class ViewportHost {
     rotationDegrees: Vec3,
     size: Vec3
   ) {
-    const contactBounds: GeneratedColliderBounds[] = [];
+    const contactBounds: Parameters<typeof collectWaterContactPatches>[1] = [];
 
     for (const brush of Object.values(document.brushes)) {
       if (brush.id === excludedBrushId || brush.volume.mode !== "none") {
         continue;
       }
 
-      contactBounds.push(getBoxBrushBounds(brush));
+      contactBounds.push({
+        kind: "orientedBox",
+        center: brush.center,
+        rotationDegrees: brush.rotationDegrees,
+        size: brush.size
+      });
     }
 
     for (const modelInstance of getModelInstances(document.modelInstances)) {
diff --git a/tests/domain/water-material.test.ts b/tests/domain/water-material.test.ts
index 326a69db..9b3b8144 100644
--- a/tests/domain/water-material.test.ts
+++ b/tests/domain/water-material.test.ts
@@ -84,6 +84,52 @@ describe("water material helpers", () => {
     expect(patches).toHaveLength(0);
   });
 
+  it("preserves oriented contact regions for rotated boxes", () => {
+    const patches = collectWaterContactPatches(
+      {
+        center: {
+          x: 0,
+          y: 0,
+          z: 0
+        },
+        rotationDegrees: {
+          x: 0,
+          y: 0,
+          z: 0
+        },
+        size: {
+          x: 10,
+          y: 2,
+          z: 10
+        }
+      },
+      [
+        {
+          kind: "orientedBox",
+          center: {
+            x: 0,
+            y: 1,
+            z: 0
+          },
+          rotationDegrees: {
+            x: 0,
+            y: 45,
+            z: 0
+          },
+          size: {
+            x: 2,
+            y: 1,
+            z: 1
+          }
+        }
+      ]
+    );
+
+    expect(patches).toHaveLength(1);
+    expect(Math.abs(patches[0]?.axisX ?? 0)).toBeGreaterThan(0.65);
+    expect(Math.abs(patches[0]?.axisZ ?? 0)).toBeGreaterThan(0.65);
+  });
+
   it("builds a shared quality shader material for visible tinted water", () => {
     const result = createWaterMaterial({
       colorHex: "#4da6d9",