diff --git a/src/spline-corridor/spline-corridor-colliders.ts b/src/spline-corridor/spline-corridor-colliders.ts
new file mode 100644
index 00000000..a489ab1c
--- /dev/null
+++ b/src/spline-corridor/spline-corridor-colliders.ts
@@ -0,0 +1,378 @@
+import type { Vec3 } from "../core/vector";
+import {
+  resolveScenePath,
+  type ScenePathCurveMode,
+  type ScenePathPoint,
+  type ScenePathRepeater,
+  type ScenePathRoadSettings
+} from "../document/paths";
+import {
+  sampleTerrainHeightAtWorldPosition,
+  type Terrain
+} from "../document/terrains";
+
+import { deriveSplineRepeaterInstances } from "./spline-repeaters";
+
+export interface SplineCorridorColliderPathPointLike {
+  id?: string;
+  pointId?: string;
+  position: Vec3;
+}
+
+export interface SplineCorridorColliderPathLike {
+  id: string;
+  visible: boolean;
+  enabled: boolean;
+  loop: boolean;
+  curveMode?: ScenePathCurveMode;
+  sampledResolution?: number;
+  glueToTerrain?: boolean;
+  terrainOffset?: number;
+  road: ScenePathRoadSettings;
+  repeaters: readonly ScenePathRepeater[];
+  points: readonly SplineCorridorColliderPathPointLike[];
+}
+
+export interface SplineCorridorBoxCollider {
+  kind: "box";
+  source: "splineCorridor";
+  colliderId: string;
+  pathId: string;
+  repeaterId?: string;
+  assetId?: string;
+  edgeSide?: "left" | "right";
+  position: Vec3;
+  rotationDegrees: Vec3;
+  center: Vec3;
+  size: Vec3;
+  worldBounds: {
+    min: Vec3;
+    max: Vec3;
+  };
+}
+
+const MIN_COLLIDER_SIZE = 0.05;
+
+function cloneVec3(vector: Vec3): Vec3 {
+  return {
+    x: vector.x,
+    y: vector.y,
+    z: vector.z
+  };
+}
+
+function normalizePathPoint(
+  point: SplineCorridorColliderPathPointLike,
+  index: number
+): ScenePathPoint {
+  return {
+    id: point.id ?? point.pointId ?? `spline-collider-point-${index}`,
+    position: cloneVec3(point.position)
+  };
+}
+
+function normalizeHorizontal(vector: Vec3): Vec3 | null {
+  const length = Math.hypot(vector.x, vector.z);
+
+  if (length <= 1e-8) {
+    return null;
+  }
+
+  return {
+    x: vector.x / length,
+    y: 0,
+    z: vector.z / length
+  };
+}
+
+function sampleHighestTerrainWorldY(
+  terrains: readonly Terrain[],
+  position: Vec3
+): number | null {
+  let highestWorldY: number | null = null;
+
+  for (const terrain of terrains) {
+    const height = sampleTerrainHeightAtWorldPosition(
+      terrain,
+      position.x,
+      position.z,
+      false
+    );
+
+    if (height === null) {
+      continue;
+    }
+
+    const worldY = terrain.position.y + height;
+
+    if (highestWorldY === null || worldY > highestWorldY) {
+      highestWorldY = worldY;
+    }
+  }
+
+  return highestWorldY;
+}
+
+function rotateY(point: Vec3, yawRadians: number): Vec3 {
+  const sin = Math.sin(yawRadians);
+  const cos = Math.cos(yawRadians);
+
+  return {
+    x: point.x * cos + point.z * sin,
+    y: point.y,
+    z: -point.x * sin + point.z * cos
+  };
+}
+
+function computeBoxWorldBounds(options: {
+  position: Vec3;
+  yawDegrees: number;
+  center: Vec3;
+  size: Vec3;
+}): { min: Vec3; max: Vec3 } {
+  const yawRadians = (options.yawDegrees * Math.PI) / 180;
+  const halfSize = {
+    x: options.size.x * 0.5,
+    y: options.size.y * 0.5,
+    z: options.size.z * 0.5
+  };
+  const min = {
+    x: Number.POSITIVE_INFINITY,
+    y: Number.POSITIVE_INFINITY,
+    z: Number.POSITIVE_INFINITY
+  };
+  const max = {
+    x: Number.NEGATIVE_INFINITY,
+    y: Number.NEGATIVE_INFINITY,
+    z: Number.NEGATIVE_INFINITY
+  };
+
+  for (const x of [-halfSize.x, halfSize.x]) {
+    for (const y of [-halfSize.y, halfSize.y]) {
+      for (const z of [-halfSize.z, halfSize.z]) {
+        const localCorner = {
+          x: options.center.x + x,
+          y: options.center.y + y,
+          z: options.center.z + z
+        };
+        const rotatedCorner = rotateY(localCorner, yawRadians);
+        const worldCorner = {
+          x: options.position.x + rotatedCorner.x,
+          y: options.position.y + rotatedCorner.y,
+          z: options.position.z + rotatedCorner.z
+        };
+
+        min.x = Math.min(min.x, worldCorner.x);
+        min.y = Math.min(min.y, worldCorner.y);
+        min.z = Math.min(min.z, worldCorner.z);
+        max.x = Math.max(max.x, worldCorner.x);
+        max.y = Math.max(max.y, worldCorner.y);
+        max.z = Math.max(max.z, worldCorner.z);
+      }
+    }
+  }
+
+  return { min, max };
+}
+
+function createBoxCollider(options: {
+  colliderId: string;
+  pathId: string;
+  repeaterId?: string;
+  assetId?: string;
+  edgeSide?: "left" | "right";
+  position: Vec3;
+  yawDegrees: number;
+  center: Vec3;
+  size: Vec3;
+}): SplineCorridorBoxCollider {
+  const size = {
+    x: Math.max(MIN_COLLIDER_SIZE, options.size.x),
+    y: Math.max(MIN_COLLIDER_SIZE, options.size.y),
+    z: Math.max(MIN_COLLIDER_SIZE, options.size.z)
+  };
+
+  return {
+    kind: "box",
+    source: "splineCorridor",
+    colliderId: options.colliderId,
+    pathId: options.pathId,
+    repeaterId: options.repeaterId,
+    assetId: options.assetId,
+    edgeSide: options.edgeSide,
+    position: cloneVec3(options.position),
+    rotationDegrees: {
+      x: 0,
+      y: options.yawDegrees,
+      z: 0
+    },
+    center: cloneVec3(options.center),
+    size,
+    worldBounds: computeBoxWorldBounds({
+      position: options.position,
+      yawDegrees: options.yawDegrees,
+      center: options.center,
+      size
+    })
+  };
+}
+
+function buildRepeaterColliders(options: {
+  path: SplineCorridorColliderPathLike;
+  terrains: readonly Terrain[];
+}): SplineCorridorBoxCollider[] {
+  const collisionRepeaterIds = new Set(
+    options.path.repeaters
+      .filter((repeater) => repeater.collisionEnabled)
+      .map((repeater) => repeater.id)
+  );
+
+  if (collisionRepeaterIds.size === 0) {
+    return [];
+  }
+
+  return deriveSplineRepeaterInstances({
+    path: options.path,
+    terrains: options.terrains
+  })
+    .filter((instance) => collisionRepeaterIds.has(instance.repeaterId))
+    .map((instance, index) => {
+      const size = {
+        x: instance.asset.dimensions.widthX * instance.scale,
+        y: instance.asset.dimensions.heightY * instance.scale,
+        z: instance.asset.dimensions.lengthZ * instance.scale
+      };
+
+      return createBoxCollider({
+        colliderId: `${instance.pathId}:${instance.repeaterId}:${index}:box`,
+        pathId: instance.pathId,
+        repeaterId: instance.repeaterId,
+        assetId: instance.asset.id,
+        position: instance.position,
+        yawDegrees: instance.yawDegrees,
+        center: {
+          x: 0,
+          y: size.y * 0.5,
+          z: 0
+        },
+        size
+      });
+    });
+}
+
+function buildRoadEdgeColliders(options: {
+  path: SplineCorridorColliderPathLike;
+  terrains: readonly Terrain[];
+}): SplineCorridorBoxCollider[] {
+  const { path, terrains } = options;
+
+  if (!path.enabled || !path.visible || !path.road.enabled) {
+    return [];
+  }
+
+  const resolvedPath = resolveScenePath(
+    {
+      loop: path.loop,
+      curveMode: path.curveMode,
+      sampledResolution: path.sampledResolution,
+      glueToTerrain: path.glueToTerrain,
+      terrainOffset: path.terrainOffset,
+      points: path.points.map(normalizePathPoint)
+    },
+    {
+      terrains
+    }
+  );
+
+  if (resolvedPath.totalLength <= 0) {
+    return [];
+  }
+
+  const colliders: SplineCorridorBoxCollider[] = [];
+  const roadHalfWidth = path.road.width * 0.5;
+
+  for (const side of ["left", "right"] as const) {
+    const edge = path.road.edges[side];
+
+    if (!edge.enabled || !edge.collisionEnabled) {
+      continue;
+    }
+
+    const sideSign = side === "left" ? 1 : -1;
+    const offset = sideSign * (roadHalfWidth + edge.width * 0.5);
+    const boxHeight = Math.max(MIN_COLLIDER_SIZE, edge.height);
+
+    resolvedPath.segments.forEach((segment, segmentIndex) => {
+      if (segment.length <= 1e-8) {
+        return;
+      }
+
+      const tangent = normalizeHorizontal(segment.tangent);
+
+      if (tangent === null) {
+        return;
+      }
+
+      const left = {
+        x: -tangent.z,
+        y: 0,
+        z: tangent.x
+      };
+      const midpoint = {
+        x: (segment.start.x + segment.end.x) * 0.5,
+        y: (segment.start.y + segment.end.y) * 0.5,
+        z: (segment.start.z + segment.end.z) * 0.5
+      };
+      const basePosition = {
+        x: midpoint.x + left.x * offset,
+        y: midpoint.y,
+        z: midpoint.z + left.z * offset
+      };
+      const terrainWorldY = path.road.terrainConform
+        ? sampleHighestTerrainWorldY(terrains, basePosition)
+        : null;
+      const yawDegrees = (Math.atan2(tangent.x, tangent.z) * 180) / Math.PI;
+
+      colliders.push(
+        createBoxCollider({
+          colliderId: `${path.id}:road-edge:${side}:${segmentIndex}:box`,
+          pathId: path.id,
+          edgeSide: side,
+          position: {
+            x: basePosition.x,
+            y:
+              (terrainWorldY ?? basePosition.y) +
+              path.road.heightOffset +
+              boxHeight * 0.5,
+            z: basePosition.z
+          },
+          yawDegrees,
+          center: {
+            x: 0,
+            y: 0,
+            z: 0
+          },
+          size: {
+            x: edge.width,
+            y: boxHeight,
+            z: segment.length
+          }
+        })
+      );
+    });
+  }
+
+  return colliders;
+}
+
+export function deriveSplineCorridorBoxColliders(options: {
+  paths: readonly SplineCorridorColliderPathLike[];
+  terrains?: readonly Terrain[];
+}): SplineCorridorBoxCollider[] {
+  const terrains = options.terrains ?? [];
+
+  return options.paths.flatMap((path) => [
+    ...buildRoadEdgeColliders({ path, terrains }),
+    ...buildRepeaterColliders({ path, terrains })
+  ]);
+}