diff --git a/implementations/Crafter.Build-Clang.cpp b/implementations/Crafter.Build-Clang.cpp
index fc7e636..3880b21 100644
--- a/implementations/Crafter.Build-Clang.cpp
+++ b/implementations/Crafter.Build-Clang.cpp
@@ -292,36 +292,82 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
         });
     }
 
-    // Asset compilation: each .png/.obj listed in cfg.assets is run through
-    // Crafter.Asset's library (linked into crafter-build directly — see
-    // :Asset_impl) to produce the SaveCompressed .ctex/.cmesh in outputDir.
-    // Skipped if the output is newer than the source. Parallel with shaders
-    // and module compiles; cancellation participates in the same flag.
-    auto assetOutput = [](const fs::path& asset) -> std::optional<fs::path> {
-        std::string ext = asset.extension().string();
-        if (ext == ".png") return fs::path(asset.filename()).replace_extension(".ctex");
-        if (ext == ".obj") return fs::path(asset.filename()).replace_extension(".cmesh");
+    // Asset compilation: each cfg.assets entry is either a single .png/.obj
+    // file (flat output: outputDir/<filename>.ctex/cmesh — preserves the
+    // original behavior) or a directory (recursed, with the relative tree
+    // mirrored under outputDir/<dirname>/; .png/.obj are compressed, every
+    // other file is copied through unchanged). Directory mode lets mod/map
+    // trees keep their nested layout so mod.json paths like
+    // "cannon/base.cmesh" resolve correctly at runtime.
+    // Skipped per-file if the output is newer than the source. Each
+    // compress runs in its own thread; passthrough copies are bundled into
+    // a single thread to match the cfg.files pattern.
+    auto compressedName = [](const fs::path& src) -> std::optional<fs::path> {
+        std::string ext = src.extension().string();
+        if (ext == ".png") return fs::path(src.filename()).replace_extension(".ctex");
+        if (ext == ".obj") return fs::path(src.filename()).replace_extension(".cmesh");
         return std::nullopt;
     };
-    for (const fs::path& asset : config.assets) {
-        std::optional<fs::path> outName = assetOutput(asset);
-        if (!outName) {
-            buildCancelled.store(true);
-            buildError = std::format("{}: unsupported asset extension (expected .png or .obj)", asset.string());
-            break;
-        }
-        fs::path out = outputDir / *outName;
-        if (fs::exists(out) && fs::exists(asset) && fs::last_write_time(asset) <= fs::last_write_time(out)) continue;
-        threads.emplace_back([&asset, out = std::move(out), &buildError, &buildCancelled]() {
-            Progress::Task task(std::format("Compressing asset {}", asset.filename().string()));
+    auto submitCompress = [&](fs::path sourcePath, fs::path outRelative) {
+        fs::path out = outputDir / outRelative;
+        if (fs::exists(out) && fs::exists(sourcePath) && fs::last_write_time(sourcePath) <= fs::last_write_time(out)) return;
+        threads.emplace_back([sourcePath = std::move(sourcePath), out = std::move(out), &buildError, &buildCancelled]() {
+            Progress::Task task(std::format("Compressing asset {}", sourcePath.filename().string()));
             if (buildCancelled.load(std::memory_order_relaxed)) return;
-            std::string result = CompressAsset(asset, out);
+            std::error_code ec;
+            fs::create_directories(out.parent_path(), ec);
+            std::string result = CompressAsset(sourcePath, out);
             if (result.empty()) return;
             bool expected = false;
             if (buildCancelled.compare_exchange_strong(expected, true)) {
                 buildError = std::move(result);
             }
         });
+    };
+    std::vector<std::pair<fs::path, fs::path>> assetPassthroughs;
+    for (const fs::path& asset : config.assets) {
+        if (fs::is_directory(asset)) {
+            fs::path topName = asset.filename();
+            for (const auto& entry : fs::recursive_directory_iterator(asset)) {
+                if (!entry.is_regular_file()) continue;
+                fs::path rel = fs::relative(entry.path(), asset);
+                if (std::optional<fs::path> compName = compressedName(entry.path())) {
+                    submitCompress(entry.path(), topName / rel.parent_path() / *compName);
+                } else {
+                    assetPassthroughs.emplace_back(entry.path(), topName / rel);
+                }
+            }
+        } else {
+            std::optional<fs::path> outName = compressedName(asset);
+            if (!outName) {
+                buildCancelled.store(true);
+                buildError = std::format("{}: unsupported asset extension (expected .png or .obj, or a directory)", asset.string());
+                break;
+            }
+            submitCompress(asset, *outName);
+        }
+    }
+    if (!assetPassthroughs.empty()) {
+        threads.emplace_back([passthroughs = std::move(assetPassthroughs), &outputDir, &buildCancelled, &buildError]() {
+            Progress::Task task("Copying asset passthrough files");
+            if (buildCancelled.load(std::memory_order_relaxed)) return;
+            try {
+                for (const auto& [src, rel] : passthroughs) {
+                    fs::path dst = outputDir / rel;
+                    fs::create_directories(dst.parent_path());
+                    if (!fs::exists(dst)) {
+                        fs::copy_file(src, dst);
+                    } else if (fs::last_write_time(src) > fs::last_write_time(dst)) {
+                        fs::copy_file(src, dst, fs::copy_options::overwrite_existing);
+                    }
+                }
+            } catch (const std::exception& e) {
+                bool expected = false;
+                if (buildCancelled.compare_exchange_strong(expected, true)) {
+                    buildError = e.what();
+                }
+            }
+        });
     }
 
     threads.emplace_back([&config, &outputDir, &buildCancelled, &buildError]() {
@@ -679,6 +725,16 @@ BuildResult Crafter::Build(Configuration& config, std::unordered_map<fs::path, s
                     copyTree(src, outputDir / additionalFile.filename());
                 }
                 for (const fs::path& asset : dep->assets) {
+                    // Directory entry: the dep already mirrored the
+                    // (compressed + passthrough) tree under
+                    // depBinDir/<asset.filename()>/. Forward it wholesale
+                    // so our bin dir gets the same layout.
+                    if (fs::is_directory(asset)) {
+                        fs::path src = depBinDir / asset.filename();
+                        if (!fs::exists(src)) continue;
+                        copyTree(src, outputDir / asset.filename());
+                        continue;
+                    }
                     std::string ext = asset.extension().string();
                     fs::path srcName = asset.filename();
                     if (ext == ".png") srcName.replace_extension(".ctex");
diff --git a/interfaces/Crafter.Build-Clang.cppm b/interfaces/Crafter.Build-Clang.cppm
index 64d9403..2fa60bd 100644
--- a/interfaces/Crafter.Build-Clang.cppm
+++ b/interfaces/Crafter.Build-Clang.cppm
@@ -125,14 +125,23 @@ export namespace Crafter {
         std::vector<fs::path> buildFiles;
         std::vector<Define> defines;
         std::vector<Shader> shaders;
-        // Source assets (.png, .obj) compressed via Crafter.Asset's
-        // SaveCompressed → .ctex/.cmesh in this configuration's bin dir.
-        // Requires Crafter.Asset in cfg.dependencies (transitively): the
-        // build engine locates it by name and uses its library API to do
-        // the conversion (an auxiliary host-target executable, generated
-        // once per build host, links Crafter.Asset and is invoked per
-        // asset). Forwarded to a consuming executable's bin dir alongside
-        // .spv shaders and cfg.files entries.
+        // Source assets compressed via Crafter.Asset's SaveCompressed →
+        // .ctex/.cmesh in this configuration's bin dir.
+        //
+        // Each entry is either:
+        //   - A single .png/.obj file. Output lands flat in the bin dir:
+        //     bin/<filename>.ctex or bin/<filename>.cmesh.
+        //   - A directory. The build recurses; .png/.obj are compressed
+        //     with the relative tree mirrored under bin/<dirname>/, and
+        //     every other file in the tree is copied through unchanged.
+        //     Lets mod/map trees (mod.json + cannon/base.obj +
+        //     cannon/color.png) keep their nested layout so JSON paths
+        //     like "cannon/base.cmesh" resolve at runtime.
+        //
+        // Crafter.Asset must be reachable through cfg.dependencies (the
+        // build engine links its library API into crafter-build via a
+        // self-host pass). Forwarded to a consuming executable's bin dir
+        // alongside .spv shaders and cfg.files entries.
         std::vector<fs::path> assets;
         std::vector<ExternalDependency> externalDependencies;
         std::vector<std::string> compileFlags;