diff --git a/res/content/base/generators/demo.files/script.lua b/res/content/base/generators/demo.files/script.lua
index cd443163..7c103090 100644
--- a/res/content/base/generators/demo.files/script.lua
+++ b/res/content/base/generators/demo.files/script.lua
@@ -1,3 +1,13 @@
+-- Get entry-point and filename from `entry-point:filename` path 
+-- // TODO: move to stdmin
+function parse_path(path)
+    local index = string.find(path, ':')
+    if index == nil then
+        error("invalid path syntax (':' missing)")
+    end
+    return string.sub(path, 1, index-1), string.sub(path, index+1, -1)
+end
+
 local _, dir = parse_path(__DIR__)
 ores = file.read_combined_list(dir.."/ores.json")
 
@@ -26,6 +36,17 @@ end
 function place_structures(x, z, w, d, seed, hmap, chunk_height)
     local placements = {}
     place_ores(placements, x, z, w, d, seed, hmap, chunk_height)
+
+    if math.random() < 0.1 then -- generate caves
+        local sy = math.random() * (chunk_height / 2)
+        local ey = math.random() * (chunk_height / 2)
+        local sx = x + math.random() * 20 - 10
+        local ex = x + math.random() * 20 - 10
+        local sz = z + math.random() * 20 - 10
+        local ez = z + math.random() * 20 - 10
+        table.insert(placements, 
+            {":line", 0, {sx - 10, sy, sz - 10}, {ex + 10, ey, ez + 10}, 3})
+    end
     return placements
 end
 
diff --git a/res/generators/default.files/script.lua b/res/generators/default.files/script.lua
deleted file mode 100644
index 1bec4cab..00000000
--- a/res/generators/default.files/script.lua
+++ /dev/null
@@ -1,23 +0,0 @@
--- TODO: delete this file after caves complete implementation
-
-function generate_heightmap(x, y, w, h, seed, s)
-    local map = Heightmap(w, h)
-    map:add(0.25)
-    return map
-end
-
-
-function place_structures(x, z, w, d, seed, hmap, chunk_height)
-    local placements = {}
-    do
-        local sy = math.random() * (chunk_height / 4)
-        local ey = math.random() * (chunk_height / 4)
-        local sx = x + math.random() * 20 - 10
-        local ex = x + math.random() * 20 - 10
-        local sz = z + math.random() * 20 - 10
-        local ez = z + math.random() * 20 - 10
-        table.insert(placements, 
-            {":line", 0, {sx - 10, sy, sz - 10}, {ex + 10, ey, ez + 10}, 3})
-    end
-    return placements
-end
diff --git a/src/world/generator/WorldGenerator.cpp b/src/world/generator/WorldGenerator.cpp
index b29914c7..daf22ece 100644
--- a/src/world/generator/WorldGenerator.cpp
+++ b/src/world/generator/WorldGenerator.cpp
@@ -341,7 +341,13 @@ void WorldGenerator::generate(voxel* voxels, int chunkX, int chunkZ) {
             }
         }
     }
+    generateLines(prototype, voxels, chunkX, chunkZ);
+    generateStructures(prototype, voxels, chunkX, chunkZ);
+}
 
+void WorldGenerator::generateStructures(
+    const ChunkPrototype& prototype, voxel* voxels, int chunkX, int chunkZ
+) {
     for (const auto& placement : prototype.structures) {
         if (placement.structure < 0 || placement.structure >= def.structures.size()) {
             logger.error() << "invalid structure index " << placement.structure;
@@ -380,7 +386,6 @@ void WorldGenerator::generate(voxel* voxels, int chunkX, int chunkZ) {
             }
         }
     }
-    generateLines(prototype, voxels, chunkX, chunkZ);
 }
 
 void WorldGenerator::generateLines(
diff --git a/src/world/generator/WorldGenerator.hpp b/src/world/generator/WorldGenerator.hpp
index 784b4329..e40ce92f 100644
--- a/src/world/generator/WorldGenerator.hpp
+++ b/src/world/generator/WorldGenerator.hpp
@@ -80,6 +80,9 @@ class WorldGenerator {
     void generateLines(
         const ChunkPrototype& prototype, voxel* voxels, int x, int z
     );
+    void generateStructures(
+        const ChunkPrototype& prototype, voxel* voxels, int x, int z
+    );
 public:
     WorldGenerator(
         const GeneratorDef& def,