diff --git a/CMakeLists.txt b/CMakeLists.txt
index df438a4a..72ee8156 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -592,6 +592,7 @@ set(WOWEE_SOURCES
     src/pipeline/wowee_terrain_loader.cpp
     src/pipeline/wowee_model.cpp
     src/pipeline/wowee_building.cpp
+    src/pipeline/wowee_collision.cpp
     src/pipeline/custom_zone_discovery.cpp
     src/pipeline/dbc_layout.cpp
 
@@ -1323,6 +1324,7 @@ add_executable(wowee_editor
     src/pipeline/wowee_terrain_loader.cpp
     src/pipeline/wowee_model.cpp
     src/pipeline/wowee_building.cpp
+    src/pipeline/wowee_collision.cpp
     src/pipeline/custom_zone_discovery.cpp
     src/pipeline/terrain_mesh.cpp
 
diff --git a/include/pipeline/wowee_collision.hpp b/include/pipeline/wowee_collision.hpp
new file mode 100644
index 00000000..9d047b27
--- /dev/null
+++ b/include/pipeline/wowee_collision.hpp
@@ -0,0 +1,54 @@
+#pragma once
+
+#include <glm/glm.hpp>
+#include <string>
+#include <vector>
+#include <cstdint>
+
+namespace wowee {
+namespace pipeline {
+
+struct ADTTerrain;
+
+// Wowee Open Collision format (.woc) — walkability mesh for custom zones
+struct WoweeCollision {
+    struct Triangle {
+        glm::vec3 v0, v1, v2;
+        uint8_t flags;  // 0x01=walkable, 0x02=water, 0x04=steep, 0x08=indoor
+    };
+
+    struct BoundingBox {
+        glm::vec3 min{1e30f}, max{-1e30f};
+        void expand(const glm::vec3& p) {
+            min = glm::min(min, p);
+            max = glm::max(max, p);
+        }
+    };
+
+    std::vector<Triangle> triangles;
+    BoundingBox bounds;
+    uint32_t tileX = 0, tileY = 0;
+
+    bool isValid() const { return !triangles.empty(); }
+    size_t walkableCount() const;
+    size_t steepCount() const;
+};
+
+class WoweeCollisionBuilder {
+public:
+    // Generate collision mesh from terrain heightmap
+    static WoweeCollision fromTerrain(const ADTTerrain& terrain,
+                                       float steepAngle = 50.0f);
+
+    // Save collision mesh to binary file
+    static bool save(const WoweeCollision& collision, const std::string& path);
+
+    // Load collision mesh from binary file
+    static WoweeCollision load(const std::string& path);
+
+    // Check if a collision file exists
+    static bool exists(const std::string& basePath);
+};
+
+} // namespace pipeline
+} // namespace wowee
diff --git a/src/pipeline/wowee_collision.cpp b/src/pipeline/wowee_collision.cpp
new file mode 100644
index 00000000..6060139a
--- /dev/null
+++ b/src/pipeline/wowee_collision.cpp
@@ -0,0 +1,176 @@
+#include "pipeline/wowee_collision.hpp"
+#include "pipeline/adt_loader.hpp"
+#include "core/logger.hpp"
+#include <fstream>
+#include <filesystem>
+#include <cstring>
+#include <cmath>
+
+namespace wowee {
+namespace pipeline {
+
+static constexpr uint32_t WOC_MAGIC = 0x31434F57; // "WOC1"
+
+size_t WoweeCollision::walkableCount() const {
+    size_t n = 0;
+    for (const auto& t : triangles)
+        if (t.flags & 0x01) n++;
+    return n;
+}
+
+size_t WoweeCollision::steepCount() const {
+    size_t n = 0;
+    for (const auto& t : triangles)
+        if (t.flags & 0x04) n++;
+    return n;
+}
+
+WoweeCollision WoweeCollisionBuilder::fromTerrain(const ADTTerrain& terrain,
+                                                    float steepAngle) {
+    WoweeCollision col;
+    col.tileX = terrain.coord.x;
+    col.tileY = terrain.coord.y;
+
+    float steepCos = std::cos(steepAngle * 3.14159265f / 180.0f);
+
+    float tileSize = 533.33333f;
+    float chunkSize = tileSize / 16.0f;
+    float vertSpacing = chunkSize / 8.0f;
+
+    for (int ci = 0; ci < 256; ci++) {
+        const auto& chunk = terrain.chunks[ci];
+        if (!chunk.hasHeightMap()) continue;
+
+        int cx = ci % 16;
+        int cy = ci / 16;
+        float chunkBaseX = (32.0f - terrain.coord.y) * tileSize - cy * chunkSize;
+        float chunkBaseY = (32.0f - terrain.coord.x) * tileSize - cx * chunkSize;
+
+        bool isHoleChunk = (chunk.holes != 0);
+
+        // Build outer vertex grid (9x9)
+        for (int row = 0; row < 8; row++) {
+            for (int col2 = 0; col2 < 8; col2++) {
+                // Check hole mask (4x4 grid, each bit covers 2x2 sub-quads)
+                if (isHoleChunk) {
+                    int hx = col2 / 2, hy = row / 2;
+                    if (chunk.holes & (1 << (hy * 4 + hx))) continue;
+                }
+
+                int i00 = row * 17 + col2;
+                int i10 = row * 17 + col2 + 1;
+                int i01 = (row + 1) * 17 + col2;
+                int i11 = (row + 1) * 17 + col2 + 1;
+
+                auto vtx = [&](int idx) -> glm::vec3 {
+                    int r = idx / 17, c = idx % 17;
+                    float x = chunkBaseX - r * vertSpacing;
+                    float y = chunkBaseY - c * vertSpacing;
+                    float z = chunk.position[2] + chunk.heightMap.heights[idx];
+                    return glm::vec3(x, y, z);
+                };
+
+                glm::vec3 v00 = vtx(i00), v10 = vtx(i10);
+                glm::vec3 v01 = vtx(i01), v11 = vtx(i11);
+
+                auto classifyTri = [&](const glm::vec3& a, const glm::vec3& b, const glm::vec3& c) {
+                    WoweeCollision::Triangle tri;
+                    tri.v0 = a; tri.v1 = b; tri.v2 = c;
+
+                    glm::vec3 normal = glm::normalize(glm::cross(b - a, c - a));
+                    float nz = std::abs(normal.z);
+
+                    tri.flags = 0;
+                    if (nz >= steepCos)
+                        tri.flags |= 0x01; // walkable
+                    else
+                        tri.flags |= 0x04; // steep
+
+                    col.bounds.expand(a);
+                    col.bounds.expand(b);
+                    col.bounds.expand(c);
+                    col.triangles.push_back(tri);
+                };
+
+                classifyTri(v00, v10, v01);
+                classifyTri(v10, v11, v01);
+            }
+        }
+
+        // Mark water triangles
+        if (terrain.waterData[ci].hasWater()) {
+            float waterH = terrain.waterData[ci].layers[0].maxHeight;
+            for (size_t ti = col.triangles.size() - 128; ti < col.triangles.size(); ti++) {
+                auto& tri = col.triangles[ti];
+                float avgZ = (tri.v0.z + tri.v1.z + tri.v2.z) / 3.0f;
+                if (avgZ < waterH) tri.flags |= 0x02;
+            }
+        }
+    }
+
+    LOG_INFO("Collision mesh: ", col.triangles.size(), " triangles (",
+             col.walkableCount(), " walkable, ", col.steepCount(), " steep)");
+    return col;
+}
+
+bool WoweeCollisionBuilder::save(const WoweeCollision& collision, const std::string& path) {
+    namespace fs = std::filesystem;
+    fs::create_directories(fs::path(path).parent_path());
+
+    std::ofstream f(path, std::ios::binary);
+    if (!f) return false;
+
+    f.write(reinterpret_cast<const char*>(&WOC_MAGIC), 4);
+    uint32_t triCount = static_cast<uint32_t>(collision.triangles.size());
+    f.write(reinterpret_cast<const char*>(&triCount), 4);
+    f.write(reinterpret_cast<const char*>(&collision.tileX), 4);
+    f.write(reinterpret_cast<const char*>(&collision.tileY), 4);
+    f.write(reinterpret_cast<const char*>(&collision.bounds.min), 12);
+    f.write(reinterpret_cast<const char*>(&collision.bounds.max), 12);
+
+    for (const auto& tri : collision.triangles) {
+        f.write(reinterpret_cast<const char*>(&tri.v0), 12);
+        f.write(reinterpret_cast<const char*>(&tri.v1), 12);
+        f.write(reinterpret_cast<const char*>(&tri.v2), 12);
+        f.write(reinterpret_cast<const char*>(&tri.flags), 1);
+    }
+
+    LOG_INFO("WOC saved: ", path, " (", triCount, " triangles)");
+    return true;
+}
+
+WoweeCollision WoweeCollisionBuilder::load(const std::string& path) {
+    WoweeCollision col;
+    std::ifstream f(path, std::ios::binary);
+    if (!f) return col;
+
+    uint32_t magic;
+    f.read(reinterpret_cast<char*>(&magic), 4);
+    if (magic != WOC_MAGIC) return col;
+
+    uint32_t triCount;
+    f.read(reinterpret_cast<char*>(&triCount), 4);
+    f.read(reinterpret_cast<char*>(&col.tileX), 4);
+    f.read(reinterpret_cast<char*>(&col.tileY), 4);
+    f.read(reinterpret_cast<char*>(&col.bounds.min), 12);
+    f.read(reinterpret_cast<char*>(&col.bounds.max), 12);
+
+    col.triangles.resize(triCount);
+    for (uint32_t i = 0; i < triCount; i++) {
+        auto& tri = col.triangles[i];
+        f.read(reinterpret_cast<char*>(&tri.v0), 12);
+        f.read(reinterpret_cast<char*>(&tri.v1), 12);
+        f.read(reinterpret_cast<char*>(&tri.v2), 12);
+        f.read(reinterpret_cast<char*>(&tri.flags), 1);
+    }
+
+    LOG_INFO("WOC loaded: ", path, " (", triCount, " triangles)");
+    return col;
+}
+
+bool WoweeCollisionBuilder::exists(const std::string& basePath) {
+    return std::filesystem::exists(basePath + ".woc");
+}
+
+} // namespace pipeline
+} // namespace wowee
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index cd13c5fd..7e53b4f1 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -403,6 +403,7 @@ register_test_target(test_gm_commands)
 add_executable(test_open_formats
     test_open_formats.cpp
     ${CMAKE_SOURCE_DIR}/src/pipeline/wowee_building.cpp
+    ${CMAKE_SOURCE_DIR}/src/pipeline/wowee_collision.cpp
     ${CMAKE_SOURCE_DIR}/src/pipeline/wowee_terrain_loader.cpp
     ${CMAKE_SOURCE_DIR}/src/pipeline/wmo_loader.cpp
     ${CMAKE_SOURCE_DIR}/src/core/logger.cpp
diff --git a/tests/test_open_formats.cpp b/tests/test_open_formats.cpp
index 91bcece1..dd724942 100644
--- a/tests/test_open_formats.cpp
+++ b/tests/test_open_formats.cpp
@@ -1,6 +1,7 @@
 // Tests for Wowee open format round-trips (WOM, WOB, WHM/WOT)
 #include <catch_amalgamated.hpp>
 #include "pipeline/wowee_building.hpp"
+#include "pipeline/wowee_collision.hpp"
 #include "pipeline/wmo_loader.hpp"
 #include "pipeline/wowee_terrain_loader.hpp"
 #include "pipeline/adt_loader.hpp"
@@ -262,6 +263,83 @@ TEST_CASE("WOT metadata round-trip with placements", "[wot]") {
     std::filesystem::remove(wotPath);
 }
 
+// ============== WOC Tests ==============
+
+TEST_CASE("WOC collision from flat terrain", "[woc]") {
+    ADTTerrain terrain{};
+    terrain.loaded = true;
+    terrain.coord = {32, 48};
+    for (int ci = 0; ci < 256; ci++) {
+        auto& chunk = terrain.chunks[ci];
+        chunk.heightMap.loaded = true;
+        chunk.indexX = ci % 16;
+        chunk.indexY = ci / 16;
+        chunk.position[2] = 100.0f;
+        chunk.holes = 0;
+        for (int v = 0; v < 145; v++)
+            chunk.heightMap.heights[v] = 0.0f;
+    }
+
+    auto col = WoweeCollisionBuilder::fromTerrain(terrain);
+    REQUIRE(col.isValid());
+    REQUIRE(col.triangles.size() == 256 * 64 * 2); // 8x8 quads * 2 tris * 256 chunks
+    REQUIRE(col.walkableCount() == col.triangles.size()); // flat = all walkable
+    REQUIRE(col.steepCount() == 0);
+    REQUIRE(col.tileX == 32);
+    REQUIRE(col.tileY == 48);
+}
+
+TEST_CASE("WOC save and load round-trip", "[woc]") {
+    ensureTestDir();
+
+    WoweeCollision col;
+    col.tileX = 10; col.tileY = 20;
+    WoweeCollision::Triangle tri;
+    tri.v0 = {0,0,0}; tri.v1 = {1,0,0}; tri.v2 = {0,1,0}; tri.flags = 0x01;
+    col.triangles.push_back(tri);
+    tri.v0 = {5,5,10}; tri.v1 = {6,5,10}; tri.v2 = {5,6,15}; tri.flags = 0x04;
+    col.triangles.push_back(tri);
+    col.bounds.expand({0,0,0}); col.bounds.expand({6,6,15});
+
+    std::string path = TEST_DIR + "/test_collision.woc";
+    REQUIRE(WoweeCollisionBuilder::save(col, path));
+
+    auto loaded = WoweeCollisionBuilder::load(path);
+    REQUIRE(loaded.isValid());
+    REQUIRE(loaded.triangles.size() == 2);
+    REQUIRE(loaded.tileX == 10);
+    REQUIRE(loaded.tileY == 20);
+    REQUIRE(loaded.triangles[0].flags == 0x01);
+    REQUIRE(loaded.triangles[1].flags == 0x04);
+    REQUIRE(loaded.triangles[0].v0.x == Catch::Approx(0.0f));
+    REQUIRE(loaded.triangles[1].v2.z == Catch::Approx(15.0f));
+    REQUIRE(loaded.walkableCount() == 1);
+    REQUIRE(loaded.steepCount() == 1);
+}
+
+TEST_CASE("WOC holes skip triangles", "[woc]") {
+    ADTTerrain terrain{};
+    terrain.loaded = true;
+    terrain.coord = {32, 32};
+    for (int ci = 0; ci < 256; ci++) {
+        auto& chunk = terrain.chunks[ci];
+        chunk.heightMap.loaded = true;
+        chunk.indexX = ci % 16;
+        chunk.indexY = ci / 16;
+        chunk.position[2] = 100.0f;
+        chunk.holes = 0;
+        for (int v = 0; v < 145; v++)
+            chunk.heightMap.heights[v] = 0.0f;
+    }
+    // Punch a hole in chunk 0 (all 16 sub-quads)
+    terrain.chunks[0].holes = 0xFFFF;
+
+    auto col = WoweeCollisionBuilder::fromTerrain(terrain);
+    REQUIRE(col.isValid());
+    // Chunk 0 should produce zero triangles, rest produce 128 each
+    REQUIRE(col.triangles.size() == 255 * 128);
+}
+
 TEST_CASE("WOB rejects missing file", "[wob]") {
     REQUIRE_FALSE(WoweeBuildingLoader::exists("nonexistent_path"));
 }
diff --git a/tools/editor/FORMAT_SPEC.md b/tools/editor/FORMAT_SPEC.md
index 8de90adf..207d360c 100644
--- a/tools/editor/FORMAT_SPEC.md
+++ b/tools/editor/FORMAT_SPEC.md
@@ -59,18 +59,28 @@ Novel file formats for custom WoW zone content. No Blizzard IP.
 - Standard PNG format, loaded by client's texture override system
 - Editor auto-converts BLP→PNG on export via stb_image_write
 
+## WOC — Wowee Open Collision (binary)
+- Extension: `.woc`
+- Magic: `WOC1` (0x31434F57)
+- Layout: magic(4) + triCount(4) + tileX(4) + tileY(4) + boundsMin(12) + boundsMax(12) + triangles
+- Triangle: v0(12) + v1(12) + v2(12) + flags(1) = 37 bytes
+- Flags: 0x01=walkable, 0x02=water, 0x04=steep, 0x08=indoor
+- Generated from terrain heightmap with slope classification (50 deg threshold)
+- Respects terrain holes (skips triangles in hole regions)
+
 ## Terrain Stamps (.json)
 - Portable terrain feature snapshots (mountains, craters, etc.)
 - Format: `{"format": "wowee-stamp-1.0", "vertices": [[dx, dy, height], ...]}`
 - Can be saved/loaded across zones and sessions
 
-## Open Format Scoring (0-6)
+## Open Format Scoring (0-7)
 1. WOT terrain metadata present
 2. WHM heightmap with valid magic
 3. zone.json map definition
 4. PNG textures present
 5. WOM models with valid magic
 6. WOB buildings with valid magic
+7. WOC collision mesh with valid magic
 
 ## All formats are novel, portable, and open for redistribution.
 ## No Blizzard intellectual property is used in any format definition.
diff --git a/tools/editor/content_pack.cpp b/tools/editor/content_pack.cpp
index 44ac67c0..c59c578f 100644
--- a/tools/editor/content_pack.cpp
+++ b/tools/editor/content_pack.cpp
@@ -202,6 +202,7 @@ ContentPacker::ValidationResult ContentPacker::validateZone(const std::string& z
     static constexpr uint32_t WHM_MAGIC = 0x314D4857; // "WHM1"
     static constexpr uint32_t WOM_MAGIC = 0x314D4F57; // "WOM1"
     static constexpr uint32_t WOB_MAGIC = 0x31424F57; // "WOB1"
+    static constexpr uint32_t WOC_MAGIC = 0x31434F57; // "WOC1"
 
     for (auto& entry : fs::recursive_directory_iterator(zoneDir)) {
         if (!entry.is_regular_file()) continue;
@@ -220,6 +221,10 @@ ContentPacker::ValidationResult ContentPacker::validateZone(const std::string& z
             r.hasWob = true;
             if (checkMagic(entry.path().string(), WOB_MAGIC)) r.wobValid = true;
         }
+        if (ext == ".woc") {
+            r.hasWoc = true;
+            if (checkMagic(entry.path().string(), WOC_MAGIC)) r.wocValid = true;
+        }
         if (ext == ".png") r.hasPng = true;
         if (fname == "zone.json") r.hasZoneJson = true;
         if (fname == "creatures.json") r.hasCreatures = true;
@@ -237,7 +242,8 @@ int ContentPacker::ValidationResult::openFormatScore() const {
     if (hasPng) score++;
     if (hasWom && womValid) score++;
     if (hasWob && wobValid) score++;
-    return score; // max 6 for fully open
+    if (hasWoc && wocValid) score++;
+    return score; // max 7 for fully open
 }
 
 std::string ContentPacker::ValidationResult::summary() const {
@@ -252,6 +258,7 @@ std::string ContentPacker::ValidationResult::summary() const {
     add(hasWhm, whmValid, "WHM");
     add(hasWom, womValid, "WOM");
     add(hasWob, wobValid, "WOB");
+    add(hasWoc, wocValid, "WOC");
     if (hasZoneJson) s += "zone.json ";
     if (hasPng) s += "PNG ";
     if (hasCreatures) s += "creatures ";
diff --git a/tools/editor/content_pack.hpp b/tools/editor/content_pack.hpp
index 6ba05098..d44b35d1 100644
--- a/tools/editor/content_pack.hpp
+++ b/tools/editor/content_pack.hpp
@@ -38,9 +38,9 @@ public:
     // Validate that a zone directory has all required open format files
     struct ValidationResult {
         bool hasWot = false, hasWhm = false, hasZoneJson = false;
-        bool hasPng = false, hasWom = false, hasWob = false;
+        bool hasPng = false, hasWom = false, hasWob = false, hasWoc = false;
         bool hasCreatures = false, hasQuests = false, hasObjects = false;
-        bool whmValid = false, womValid = false, wobValid = false;
+        bool whmValid = false, womValid = false, wobValid = false, wocValid = false;
         int openFormatScore() const;
         std::string summary() const;
     };
diff --git a/tools/editor/editor_app.cpp b/tools/editor/editor_app.cpp
index a6c27eb6..72b220c2 100644
--- a/tools/editor/editor_app.cpp
+++ b/tools/editor/editor_app.cpp
@@ -7,6 +7,7 @@
 #include "dbc_exporter.hpp"
 #include "pipeline/wowee_model.hpp"
 #include "pipeline/wowee_building.hpp"
+#include "pipeline/wowee_collision.hpp"
 #include "pipeline/wmo_loader.hpp"
 #include "core/coordinates.hpp"
 #include <nlohmann/json.hpp>
@@ -956,6 +957,11 @@ void EditorApp::exportZone(const std::string& outputDir) {
                            std::to_string(loadedTileX_) + "_" + std::to_string(loadedTileY_);
     WoweeTerrain::exportOpen(terrain_, openBase, loadedTileX_, loadedTileY_);
     WoweeTerrain::exportNormalMap(terrain_, openBase + "_normals.png");
+
+    // Export collision mesh (.woc)
+    auto collision = pipeline::WoweeCollisionBuilder::fromTerrain(terrain_);
+    if (collision.isValid())
+        pipeline::WoweeCollisionBuilder::save(collision, openBase + ".woc");
     WoweeTerrain::exportAlphaMaps(terrain_, base + "/alphamaps");
     WoweeTerrain::exportWaterMask(terrain_, openBase + "_watermask.png");
     WoweeTerrain::exportHoleMask(terrain_, openBase + "_holemask.png");
@@ -1059,11 +1065,11 @@ void EditorApp::exportZone(const std::string& outputDir) {
     if (objectPlacer_.objectCount() > 0) summary += ", " + std::to_string(objectPlacer_.objectCount()) + " obj";
     if (npcSpawner_.spawnCount() > 0) summary += ", " + std::to_string(npcSpawner_.spawnCount()) + " NPC";
     if (questEditor_.questCount() > 0) summary += ", " + std::to_string(questEditor_.questCount()) + " quest";
-    summary += " (score " + std::to_string(score) + "/6)";
+    summary += " (score " + std::to_string(score) + "/7)";
     showToast(summary, 5.0f);
     LOG_INFO("=== Zone Export Summary ===");
     LOG_INFO("  Output: ", base);
-    LOG_INFO("  Open format score: ", score, "/6");
+    LOG_INFO("  Open format score: ", score, "/7");
     LOG_INFO("  Formats: ", validation.summary());
     LOG_INFO("  Terrain: WOT/WHM + heightmap/normals PNG");
     LOG_INFO("  Textures: ", usedTextures.size(), " BLP→PNG");
diff --git a/tools/editor/editor_ui.cpp b/tools/editor/editor_ui.cpp
index d011d45f..3354a8ab 100644
--- a/tools/editor/editor_ui.cpp
+++ b/tools/editor/editor_ui.cpp
@@ -366,7 +366,7 @@ void EditorUI::renderMenuBar(EditorApp& app) {
                 ImVec4 scoreColor = score >= 5 ? ImVec4(0.3f, 1, 0.3f, 1) :
                                     score >= 3 ? ImVec4(1, 1, 0.3f, 1) :
                                                  ImVec4(1, 0.3f, 0.3f, 1);
-                ImGui::TextColored(scoreColor, "Open Format Score: %d/6", score);
+                ImGui::TextColored(scoreColor, "Open Format Score: %d/7", score);
                 ImGui::Separator();
                 auto fmt = [](bool has, bool valid, const char* name, const char* desc) {
                     ImVec4 c = has ? (valid ? ImVec4(0.3f,1,0.3f,1) : ImVec4(1,0.7f,0.3f,1))
@@ -380,6 +380,7 @@ void EditorUI::renderMenuBar(EditorApp& app) {
                 fmt(val.hasPng, true, "PNG", "textures");
                 fmt(val.hasWom, val.womValid, "WOM", "models");
                 fmt(val.hasWob, val.wobValid, "WOB", "buildings");
+                fmt(val.hasWoc, val.wocValid, "WOC", "collision mesh");
                 ImGui::Separator();
                 fmt(val.hasCreatures, true, "creatures", "NPC spawns");
                 fmt(val.hasQuests, true, "quests", "quest data");