diff --git a/tools/editor/main.cpp b/tools/editor/main.cpp
index 02e48836..0fc7a9c7 100644
--- a/tools/editor/main.cpp
+++ b/tools/editor/main.cpp
@@ -437,6 +437,8 @@ static void printUsage(const char* argv0) {
     std::printf("                         Convert a WOB building to Wavefront OBJ (one group per WOB group)\n");
     std::printf("  --import-wob-obj <obj-path> [wob-base]\n");
     std::printf("                         Convert a Wavefront OBJ back into WOB (round-trips with --export-wob-obj)\n");
+    std::printf("  --export-woc-obj <woc-path> [out.obj]\n");
+    std::printf("                         Convert a WOC collision mesh to OBJ for visualization (per-flag color groups)\n");
     std::printf("  --validate <zoneDir> [--json]\n");
     std::printf("                         Score zone open-format completeness and exit\n");
     std::printf("  --validate-wom <wom-base> [--json]\n");
@@ -519,6 +521,7 @@ int main(int argc, char* argv[]) {
         "--build-woc", "--regen-collision", "--fix-zone",
         "--export-png", "--export-obj", "--import-obj",
         "--export-wob-obj", "--import-wob-obj",
+        "--export-woc-obj",
         "--convert-m2", "--convert-wmo",
     };
     for (int i = 1; i < argc; i++) {
@@ -2601,6 +2604,88 @@ int main(int argc, char* argv[]) {
                 std::printf("  warning: skipped %d malformed face(s)\n", badFaces);
             }
             return 0;
+        } else if (std::strcmp(argv[i], "--export-woc-obj") == 0 && i + 1 < argc) {
+            // Visualize a WOC collision mesh in any 3D tool. Each
+            // walkability class becomes its own OBJ group (walkable /
+            // steep / water / indoor) so designers can hide categories
+            // independently in Blender to debug 'why can the player
+            // walk here?' or 'why can't they walk there?'.
+            std::string path = argv[++i];
+            std::string outPath;
+            if (i + 1 < argc && argv[i + 1][0] != '-') {
+                outPath = argv[++i];
+            }
+            if (!std::filesystem::exists(path)) {
+                std::fprintf(stderr, "WOC not found: %s\n", path.c_str());
+                return 1;
+            }
+            if (outPath.empty()) {
+                outPath = path;
+                if (outPath.size() >= 4 &&
+                    outPath.substr(outPath.size() - 4) == ".woc") {
+                    outPath = outPath.substr(0, outPath.size() - 4);
+                }
+                outPath += ".obj";
+            }
+            auto woc = wowee::pipeline::WoweeCollisionBuilder::load(path);
+            if (!woc.isValid()) {
+                std::fprintf(stderr, "WOC has no triangles: %s\n", path.c_str());
+                return 1;
+            }
+            std::ofstream obj(outPath);
+            if (!obj) {
+                std::fprintf(stderr, "Failed to open output file: %s\n", outPath.c_str());
+                return 1;
+            }
+            // Bucket triangles by flag combination so the OBJ can split
+            // them into named groups. Flag bits: walkable=0x01, water=0x02,
+            // steep=0x04, indoor=0x08 (per WoweeCollision::Triangle).
+            // Triangles can have multiple flags set so a per-flag group
+            // would over-count; instead we bucket by exact flag value.
+            std::unordered_map<uint8_t, std::vector<size_t>> byFlag;
+            for (size_t t = 0; t < woc.triangles.size(); ++t) {
+                byFlag[woc.triangles[t].flags].push_back(t);
+            }
+            obj << "# Wavefront OBJ generated by wowee_editor --export-woc-obj\n";
+            obj << "# Source: " << path << "\n";
+            obj << "# Triangles: " << woc.triangles.size()
+                << " (walkable=" << woc.walkableCount()
+                << " steep=" << woc.steepCount() << ")\n";
+            obj << "# Tile: (" << woc.tileX << ", " << woc.tileY << ")\n\n";
+            obj << "o WoweeCollision\n";
+            // Emit ALL vertices first (3 per triangle, no dedupe — the
+            // collision mesh has triangle-soup topology where shared
+            // verts often have different flags, so deduping would
+            // actually merge categories).
+            for (const auto& tri : woc.triangles) {
+                obj << "v " << tri.v0.x << " " << tri.v0.y << " " << tri.v0.z << "\n";
+                obj << "v " << tri.v1.x << " " << tri.v1.y << " " << tri.v1.z << "\n";
+                obj << "v " << tri.v2.x << " " << tri.v2.y << " " << tri.v2.z << "\n";
+            }
+            // Emit faces grouped by flag class. OBJ index of triangle t
+            // vertex k is (t * 3 + k + 1) — 1-based, three verts per tri.
+            auto flagName = [](uint8_t f) {
+                if (f == 0) return std::string("nonwalkable");
+                std::string s;
+                if (f & 0x01) s += "walkable";
+                if (f & 0x02) { if (!s.empty()) s += "_"; s += "water"; }
+                if (f & 0x04) { if (!s.empty()) s += "_"; s += "steep"; }
+                if (f & 0x08) { if (!s.empty()) s += "_"; s += "indoor"; }
+                if (s.empty()) s = "flag" + std::to_string(int(f));
+                return s;
+            };
+            for (const auto& [flag, tris] : byFlag) {
+                obj << "g " << flagName(flag) << "\n";
+                for (size_t t : tris) {
+                    uint32_t base = static_cast<uint32_t>(t * 3 + 1);
+                    obj << "f " << base << " " << (base + 1) << " " << (base + 2) << "\n";
+                }
+            }
+            obj.close();
+            std::printf("Exported %s -> %s\n", path.c_str(), outPath.c_str());
+            std::printf("  %zu triangles in %zu flag class(es), tile (%u, %u)\n",
+                        woc.triangles.size(), byFlag.size(), woc.tileX, woc.tileY);
+            return 0;
         } else if (std::strcmp(argv[i], "--import-obj") == 0 && i + 1 < argc) {
             // Convert a Wavefront OBJ back into WOM. Round-trips with
             // --export-obj for the geometry/UV/normal data; bones,