diff --git a/library/terraman_library.cpp b/library/terraman_library.cpp
index d377d55..f6e4709 100644
--- a/library/terraman_library.cpp
+++ b/library/terraman_library.cpp
@@ -69,7 +69,7 @@ Ref<Material> TerramanLibrary::material_lod_get(const int index) {
 	return _materials[index];
 }
 
-void TerramanLibrary::material_cache_get_key(const Ref<TerraChunk> &chunk) {
+void TerramanLibrary::material_cache_get_key(Ref<TerraChunk> chunk) {
 	call("_material_cache_get_key", chunk);
 }
 
@@ -143,7 +143,7 @@ Ref<Material> TerramanLibrary::liquid_material_lod_get(const int index) {
 	return _liquid_materials[index];
 }
 
-void TerramanLibrary::liquid_material_cache_get_key(const Ref<TerraChunk> &chunk) {
+void TerramanLibrary::liquid_material_cache_get_key(Ref<TerraChunk> chunk) {
 	call("_liquid_material_cache_get_key", chunk);
 }
 
@@ -217,7 +217,7 @@ Ref<Material> TerramanLibrary::prop_material_lod_get(const int index) {
 	return _prop_materials[index];
 }
 
-void TerramanLibrary::prop_material_cache_get_key(const Ref<TerraChunk> &chunk) {
+void TerramanLibrary::prop_material_cache_get_key(Ref<TerraChunk> chunk) {
 	call("_prop_material_cache_get_key", chunk);
 }
 
diff --git a/library/terraman_library.h b/library/terraman_library.h
index c362953..1ed71a7 100644
--- a/library/terraman_library.h
+++ b/library/terraman_library.h
@@ -72,7 +72,7 @@ public:
 	Ref<Material> material_get(const int index);
 	Ref<Material> material_lod_get(const int index);
 
-	void material_cache_get_key(const Ref<TerraChunk> &chunk);
+	void material_cache_get_key(Ref<TerraChunk> chunk);
 	virtual void _material_cache_get_key(Ref<TerraChunk> chunk);
 	Ref<TerraMaterialCache> material_cache_get(const int key);
 	virtual Ref<TerraMaterialCache> _material_cache_get(const int key);
@@ -89,7 +89,7 @@ public:
 	Ref<Material> liquid_material_get(const int index);
 	Ref<Material> liquid_material_lod_get(const int index);
 
-	void liquid_material_cache_get_key(const Ref<TerraChunk> &chunk);
+	void liquid_material_cache_get_key(Ref<TerraChunk> chunk);
 	virtual void _liquid_material_cache_get_key(Ref<TerraChunk> chunk);
 	Ref<TerraMaterialCache> liquid_material_cache_get(const int key);
 	virtual Ref<TerraMaterialCache> _liquid_material_cache_get(const int key);
@@ -106,7 +106,7 @@ public:
 	Ref<Material> prop_material_get(const int index);
 	Ref<Material> prop_material_lod_get(const int index);
 
-	void prop_material_cache_get_key(const Ref<TerraChunk> &chunk);
+	void prop_material_cache_get_key(Ref<TerraChunk> chunk);
 	virtual void _prop_material_cache_get_key(Ref<TerraChunk> chunk);
 	Ref<TerraMaterialCache> prop_material_cache_get(const int key);
 	virtual Ref<TerraMaterialCache> _prop_material_cache_get(const int key);