diff --git a/addons/material_maker/engine/gen_material.gd b/addons/material_maker/engine/gen_material.gd
index 39e82f6..046f79c 100644
--- a/addons/material_maker/engine/gen_material.gd
+++ b/addons/material_maker/engine/gen_material.gd
@@ -70,7 +70,6 @@ func set_parameter(p, v) -> void:
 	update_preview()
 
 func source_changed(input_index : int) -> void:
-	print("source_changed "+str(input_index))
 	for t in TEXTURE_LIST:
 		if t.has("sources") and t.sources.find(input_index) != -1:
 			generated_textures[t.texture] = null
@@ -163,7 +162,7 @@ func update_material(m, file_prefix = null) -> void:
 		else:
 			m.normal_enabled = false
 		# Depth
-		if get_source(INPUT_DEPTH) != null and parameters.depth > 0:
+		if get_source(INPUT_DEPTH) != null and parameters.depth_scale > 0:
 			m.depth_enabled = true
 			m.depth_deep_parallax = true
 			m.depth_scale = parameters.depth_scale * 0.2
@@ -203,11 +202,28 @@ func get_export_extension(profile : String) -> String:
 
 func subst_string(s : String, export_context : Dictionary) -> String:
 	for k in export_context.keys():
-		s = s.replace("$("+k+")", export_context[k])
-	for input_index in range(shader_model.inputs.size()):
-		var input = shader_model.inputs[input_index]
-		var is_input_connected = "true" if get_source(input_index) != null else "false"
-		s = s.replace("$(connected:"+input.name+")", is_input_connected)
+		s = s.replace(k, export_context[k])
+	while (true):
+		var search_string = "$(expr:"
+		var position = s.find(search_string)
+		if position == -1:
+			break
+		var parenthesis_level = 0
+		var expr_begin = position+search_string.length()
+		for i in range(expr_begin, s.length()):
+			if s[i] == '(':
+				parenthesis_level += 1
+			elif s[i] == ')':
+				if parenthesis_level == 0:
+					var expression = s.substr(expr_begin, i-expr_begin)
+					var expr = Expression.new()
+					var error = expr.parse(expression, [])
+					if error == OK:
+						s = s.replace(s.substr(position, i+1-position), str(expr.execute()))
+					else:
+						s = s.replace(s.substr(position, i+1-position), "EXPRESSION ERROR ("+expression+")")
+					break
+				parenthesis_level -= 1
 	return s
 
 func create_file_from_template(template : String, file_name : String, export_context : Dictionary) -> bool:
@@ -228,7 +244,7 @@ func create_file_from_template(template : String, file_name : String, export_con
 			var expr = Expression.new()
 			var error = expr.parse(condition, [])
 			if error != OK:
-				print("Error in expression: "+expr.get_error_text())
+				print("Error in expression "+condition+": "+expr.get_error_text())
 				continue
 			skip_state.push_back(!expr.execute())
 		elif l.left(3) == "$fi":
@@ -241,9 +257,26 @@ func create_file_from_template(template : String, file_name : String, export_con
 
 func export_material(prefix, profile) -> void:
 	var export_context : Dictionary = {
-		path_prefix=prefix,
-		file_prefix=prefix.get_file()
+		"$(path_prefix)":prefix,
+		"$(file_prefix)":prefix.get_file()
 	}
+	for i in range(shader_model.inputs.size()):
+		var input = shader_model.inputs[i]
+		export_context["$(connected:"+input.name+")"] = "true" if get_source(i) != null else "false"
+	for p in shader_model.parameters:
+		var value = p.default
+		if parameters.has(p.name):
+			value = parameters[p.name]
+		match p.type:
+			"float", "size":
+				export_context["$(param:"+p.name+")"] = str(value)
+			"color":
+				export_context["$(param:"+p.name+".r)"] = str(value.r)
+				export_context["$(param:"+p.name+".g)"] = str(value.g)
+				export_context["$(param:"+p.name+".b)"] = str(value.b)
+				export_context["$(param:"+p.name+".a)"] = str(value.a)
+			_:
+				print(p.type+" not supported in material")
 	for f in shader_model.exports[profile].files:
 		match f.type:
 			"texture":
diff --git a/addons/material_maker/engine/io_types.gd b/addons/material_maker/engine/io_types.gd
index 5bf862f..c16e324 100644
--- a/addons/material_maker/engine/io_types.gd
+++ b/addons/material_maker/engine/io_types.gd
@@ -6,17 +6,17 @@ var types : Dictionary = {}
 
 func _ready():
 	var file = File.new()
-	if file.open("res://addons/material_maker/nodes/io_types.mmt", File.READ) != OK:
-		print("Cannot read types")
-		return false
-	var type_list = parse_json(file.get_as_text())
-	file.close()
-	for t in type_list:
-		if t.has("label"):
-			type_names.push_back(t.name)
-		var c = t.color
-		t.color = Color(c.r, c.g, c.b, c.a)
-		if file.open("res://addons/material_maker/nodes/preview_"+t.name+".shader", File.READ) == OK:
-			t.preview = file.get_as_text()
+	for p in mm_loader.get_nodes_paths():
+		if file.open(p+"/io_types.mmt", File.READ) == OK:
+			var type_list = parse_json(file.get_as_text())
 			file.close()
-		types[t.name] = t
+			for t in type_list:
+				if t.has("label"):
+					type_names.push_back(t.name)
+				var c = t.color
+				t.color = Color(c.r, c.g, c.b, c.a)
+				if file.open(p+"/preview_"+t.name+".shader", File.READ) == OK:
+					t.preview = file.get_as_text()
+					file.close()
+				types[t.name] = t
+			break
diff --git a/addons/material_maker/engine/loader.gd b/addons/material_maker/engine/loader.gd
index 52281f4..97db0e4 100644
--- a/addons/material_maker/engine/loader.gd
+++ b/addons/material_maker/engine/loader.gd
@@ -8,9 +8,12 @@ var predefined_generators = {}
 func _ready()-> void:
 	update_predefined_generators()
 
+func get_nodes_paths() -> Array:
+	return [ STD_GENDEF_PATH, OS.get_executable_path().get_base_dir()+"/nodes" ]
+
 func update_predefined_generators()-> void:
 	predefined_generators = {}
-	for path in [ STD_GENDEF_PATH, OS.get_executable_path().get_base_dir()+"/generators" ]:
+	for path in get_nodes_paths():
 		var dir = Directory.new()
 		if dir.open(path) == OK:
 			dir.list_dir_begin()
@@ -24,7 +27,7 @@ func update_predefined_generators()-> void:
 				file_name = dir.get_next()
 
 func generator_name_from_path(path : String) -> String:
-	for p in [ STD_GENDEF_PATH, OS.get_executable_path().get_base_dir()+"/generators" ]:
+	for p in get_nodes_paths():
 		print(p)
 	print(path.get_base_dir())
 	return path.get_basename().get_file()
@@ -101,7 +104,7 @@ func create_gen(data) -> MMGenBase:
 func get_generator_list() -> Array:
 	var rv = []
 	var dir : Directory = Directory.new()
-	for p in [ STD_GENDEF_PATH, OS.get_executable_path().get_base_dir()+"/generators" ]:
+	for p in get_nodes_paths():
 		dir.open(p)
 		dir.list_dir_begin(true)
 		while true:
diff --git a/addons/material_maker/nodes/godot.tres.tmpl b/addons/material_maker/nodes/godot.tres.tmpl
index 7238237..fd6d6bd 100644
--- a/addons/material_maker/nodes/godot.tres.tmpl
+++ b/addons/material_maker/nodes/godot.tres.tmpl
@@ -14,34 +14,38 @@ $if $(connected:depth_tex)
 $fi
 
 [resource]
+albedo_color = Color($(param:albedo_color.r), $(param:albedo_color.g), $(param:albedo_color.b), $(param:albedo_color.a))
 $if $(connected:albedo_tex)
 albedo_texture = ExtResource( 1 )
 $fi
-metallic = 1.0
+metallic = $(param:metallic)
 $if $(connected:metallic_tex)
 metallic_texture = ExtResource( 2 )
 metallic_texture_channel = 2
 $fi
+roughness = $(param:roughness)
 $if $(connected:ao_tex) or $(connected:roughness_tex) or $(connected:metallic_tex)
 roughness_texture = ExtResource( 2 )
 roughness_texture_channel = 1
 $fi
 $if $(connected:normal_tex)
 normal_enabled = true
-normal_scale = 1.0
+normal_scale = $(param:normal)
 normal_texture = ExtResource( 3 )
 $fi
 $if $(connected:ao_tex)
 ao_enabled = true
-ao_light_affect = 0.0
+ao_light_affect = $(param:ao)
 ao_texture = ExtResource( 2 )
 ao_on_uv2 = false
 ao_texture_channel = 0
 $fi
 $if $(connected:depth_tex)
 depth_enabled = true
-depth_scale = 0.05
-depth_deep_parallax = false
+depth_scale = $(expr:0.2*$(param:depth_scale))
+depth_deep_parallax = true
+depth_min_layers = 8
+depth_max_layers = 32
 depth_flip_tangent = false
 depth_flip_binormal = false
 depth_texture = ExtResource( 4 )
diff --git a/addons/material_maker/nodes/material.mmg b/addons/material_maker/nodes/material.mmg
index b7203d8..cf49226 100644
--- a/addons/material_maker/nodes/material.mmg
+++ b/addons/material_maker/nodes/material.mmg
@@ -5,7 +5,7 @@
 		"y": 0
 	},
 	"parameters": {
-		"albedo": {
+		"albedo_color": {
 			"a": 1,
 			"b": 1,
 			"g": 1,
@@ -13,7 +13,7 @@
 			"type": "Color"
 		},
 		"ao": 1,
-		"depth": 0.5,
+		"depth_scale": 0.5,
 		"emission": 1,
 		"metallic": 1,
 		"normal": 1,
@@ -294,7 +294,7 @@
 				"label": "Depth",
 				"max": 1,
 				"min": 0,
-				"name": "depth",
+				"name": "depth_scale",
 				"step": 0.01,
 				"type": "float"
 			},