diff --git a/addons/material_maker/engine/gen_base.gd b/addons/material_maker/engine/gen_base.gd
index 86112b1..8a14838 100644
--- a/addons/material_maker/engine/gen_base.gd
+++ b/addons/material_maker/engine/gen_base.gd
@@ -90,8 +90,8 @@ func init_parameters() -> void:
 
 func set_position(p) -> void:
 	position = p
-	if has_randomness() and !is_seed_locked():
-		source_changed(0)
+	if has_randomness() and !is_seed_locked() and is_inside_tree():
+		get_tree().call_group("preview", "on_float_parameter_changed", "seed_o%s" % [ str(get_instance_id()) ], get_seed())
 
 func get_type() -> String:
 	return "generic"
diff --git a/addons/material_maker/engine/gen_buffer.gd b/addons/material_maker/engine/gen_buffer.gd
index a412302..ad20999 100644
--- a/addons/material_maker/engine/gen_buffer.gd
+++ b/addons/material_maker/engine/gen_buffer.gd
@@ -37,8 +37,9 @@ func get_output_defs() -> Array:
 	return [ { type="rgba" }, { type="rgba" } ]
 
 func source_changed(_input_port_index : int) -> void:
-	if !is_inside_tree():
-		return
+	call_deferred("update_shader")
+
+func update_shader() -> void:
 	var context : MMGenContext = MMGenContext.new()
 	var source = {}
 	var source_output = get_source(0)
@@ -73,7 +74,7 @@ func update_buffer() -> void:
 		updating = true
 		while update_again:
 			update_again = false
-			var result = mm_renderer.render_material(material, pow(2, parameters.size))
+			var result = mm_renderer.render_material(material, pow(2, get_parameter("size")))
 			while result is GDScriptFunctionState:
 				result = yield(result, "completed")
 			if !update_again:
diff --git a/addons/material_maker/engine/gen_shader.gd b/addons/material_maker/engine/gen_shader.gd
index a93e384..1e7fcc7 100644
--- a/addons/material_maker/engine/gen_shader.gd
+++ b/addons/material_maker/engine/gen_shader.gd
@@ -18,9 +18,11 @@ func toggle_editable() -> bool:
 func is_editable() -> bool:
 	return editable
 
+
 func has_randomness() -> bool:
 	return uses_seed
 
+
 func get_type() -> String:
 	return "shader"
 
@@ -178,7 +180,7 @@ func subst(string : String, context : MMGenContext, uv : String = "") -> Diction
 	if uv != "":
 		var genname_uv = genname+"_"+str(context.get_variant(self, uv))
 		string = replace_variable(string, "name_uv", genname_uv)
-	var tmp_string = replace_variable(string, "seed", str(get_seed()))
+	var tmp_string = replace_variable(string, "seed", "seed_"+genname)
 	if tmp_string != string:
 		string = tmp_string
 	if shader_model.has("parameters") and typeof(shader_model.parameters) == TYPE_ARRAY:
@@ -246,6 +248,8 @@ func _get_shader_code(uv : String, output_index : int, context : MMGenContext) -
 		var output = shader_model.outputs[output_index]
 		if !context.has_variant(self):
 			# Generate functions for gradients
+			if has_randomness():
+				rv.defs += "uniform int seed_%s = %d;\n" % [ genname, get_seed() ]
 			for p in shader_model.parameters:
 				if p.type == "float":
 					rv.defs += "uniform float p_%s_%s = %.9f;\n" % [ genname, p.name, parameters[p.name] ]
diff --git a/addons/material_maker/nodes/beehive.mmg b/addons/material_maker/nodes/beehive.mmg
index 15f901f..9e9ca63 100644
--- a/addons/material_maker/nodes/beehive.mmg
+++ b/addons/material_maker/nodes/beehive.mmg
@@ -22,7 +22,7 @@
 				"type": "f"
 			},
 			{
-				"rgb": "rand3(fract($(name_uv)_center.zw/vec2($sx, $sy))+vec2($seed))",
+				"rgb": "rand3(fract($(name_uv)_center.zw/vec2($sx, $sy))+vec2(float($seed)))",
 				"type": "rgb"
 			},
 			{
diff --git a/addons/material_maker/nodes/bricks.mmg b/addons/material_maker/nodes/bricks.mmg
index aba14ac..cc365bb 100644
--- a/addons/material_maker/nodes/bricks.mmg
+++ b/addons/material_maker/nodes/bricks.mmg
@@ -29,7 +29,7 @@
 				"type": "f"
 			},
 			{
-				"rgb": "rand3(fract($(name_uv)_rect.xy)+rand2(vec2($seed)))",
+				"rgb": "rand3(fract($(name_uv)_rect.xy)+rand2(vec2(float($seed))))",
 				"type": "rgb"
 			},
 			{
diff --git a/addons/material_maker/nodes/splatter.mmg b/addons/material_maker/nodes/splatter.mmg
index 921f71c..1362b70 100644
--- a/addons/material_maker/nodes/splatter.mmg
+++ b/addons/material_maker/nodes/splatter.mmg
@@ -33,7 +33,7 @@
 		"name": "Splatter",
 		"outputs": [
 			{
-				"f": "splatter_$(name)($uv, int($count), vec2($seed))",
+				"f": "splatter_$(name)($uv, int($count), vec2(float($seed)))",
 				"type": "f"
 			}
 		],
diff --git a/addons/material_maker/nodes/splatter_color.mmg b/addons/material_maker/nodes/splatter_color.mmg
index 4158172..32ae9d7 100644
--- a/addons/material_maker/nodes/splatter_color.mmg
+++ b/addons/material_maker/nodes/splatter_color.mmg
@@ -33,7 +33,7 @@
 		"name": "Color Splatter",
 		"outputs": [
 			{
-				"rgba": "splatter_$(name)($uv, int($count), vec2($seed))",
+				"rgba": "splatter_$(name)($uv, int($count), vec2(float($seed)))",
 				"type": "rgba"
 			}
 		],
diff --git a/addons/material_maker/nodes/tiler.mmg b/addons/material_maker/nodes/tiler.mmg
index 7469b84..672c963 100644
--- a/addons/material_maker/nodes/tiler.mmg
+++ b/addons/material_maker/nodes/tiler.mmg
@@ -36,7 +36,7 @@
 		"name": "Tiler",
 		"outputs": [
 			{
-				"f": "tiler_$(name)($uv, vec2($tx, $ty), int($overlap), vec2($seed))",
+				"f": "tiler_$(name)($uv, vec2($tx, $ty), int($overlap), vec2(float($seed)))",
 				"type": "f"
 			}
 		],
diff --git a/addons/material_maker/nodes/tiler_color.mmg b/addons/material_maker/nodes/tiler_color.mmg
index ecc07d9..3164a1c 100644
--- a/addons/material_maker/nodes/tiler_color.mmg
+++ b/addons/material_maker/nodes/tiler_color.mmg
@@ -36,7 +36,7 @@
 		"name": "Color Tiler",
 		"outputs": [
 			{
-				"rgba": "tiler_$(name)($uv, vec2($tx, $ty), int($overlap), vec2($seed))",
+				"rgba": "tiler_$(name)($uv, vec2($tx, $ty), int($overlap), vec2(float($seed)))",
 				"type": "rgba"
 			}
 		],
diff --git a/material_maker/library/base.json b/material_maker/library/base.json
index a2962cc..e93c12d 100644
--- a/material_maker/library/base.json
+++ b/material_maker/library/base.json
@@ -4854,6 +4854,9 @@
 		{
 			"collapsed": true,
 			"icon": "miscellaneous_buffer",
+			"parameters": {
+				"size": 9
+			},
 			"tree_item": "Miscellaneous/Buffer",
 			"type": "buffer"
 		},
diff --git a/material_maker/nodes/generic.gd b/material_maker/nodes/generic.gd
index b8c1dd9..1610519 100644
--- a/material_maker/nodes/generic.gd
+++ b/material_maker/nodes/generic.gd
@@ -5,7 +5,8 @@ var controls = {}
 var ignore_parameter_change = ""
 var output_count = 0
 
-var preview : TextureRect
+var preview : ColorRect
+#var preview : TextureRect
 var preview_index : int = -1
 var preview_position : int
 var preview_size : int
@@ -151,7 +152,8 @@ func save_preview_widget() -> void:
 
 func restore_preview_widget() -> void:
 	if preview == null:
-		preview = TextureRect.new()
+		preview = preload("res://material_maker/preview/preview_2d.tscn").instance()
+		preview.shader = "uniform vec2 size;void fragment() {COLOR = preview_2d(UV);}"
 		preview.visible = false
 	preview_position = get_child_count()
 	if preview.visible:
@@ -372,14 +374,9 @@ func update_preview(size : int = 0) -> void:
 	preview_timer.start(0.2)
 
 func do_update_preview() -> void:
-	var result = generator.render(preview_index, preview_size, true)
-	while result is GDScriptFunctionState:
-		result = yield(result, "completed")
-	if preview.texture == null:
-		preview.texture = ImageTexture.new()
-	result.copy_to_texture(preview.texture)
-	result.release()
 	if !preview.visible:
 		add_child(preview)
 		move_child(preview, preview_position)
 		preview.visible = true
+	preview.set_generator(generator, preview_index)
+	preview.rect_min_size = Vector2(preview_size, preview_size)
diff --git a/material_maker/nodes/generic.tscn b/material_maker/nodes/generic.tscn
index 4b1dc50..e260792 100644
--- a/material_maker/nodes/generic.tscn
+++ b/material_maker/nodes/generic.tscn
@@ -8,3 +8,6 @@ margin_bottom = 29.0
 title = "Generic"
 show_close = true
 script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
diff --git a/material_maker/preview/preview_2d.gd b/material_maker/preview/preview_2d.gd
index 02fc14a..4cfca7e 100644
--- a/material_maker/preview/preview_2d.gd
+++ b/material_maker/preview/preview_2d.gd
@@ -23,7 +23,14 @@ func set_generator(g : MMGenBase, output : int = 0) -> void:
 		g = null
 		for c in get_children():
 			c.setup_control(generator, [])
+	# Update shader
 	material.shader.code = MMGenBase.generate_preview_shader(source, source.type, shader)
+	# Get parameter values from the shader code
+	var regex = RegEx.new()
+	regex.compile("uniform\\s+(\\w+)\\s+([\\w_\\d]+)\\s*=\\s*([^;]+);")
+	for p in regex.search_all(material.shader.code):
+		material.set_shader_param(p.strings[2], float(p.strings[3]))
+	# Set texture params
 	if source.has("textures"):
 		for k in source.textures.keys():
 			material.set_shader_param(k, source.textures[k])
diff --git a/material_maker/preview/preview_2d.tscn b/material_maker/preview/preview_2d.tscn
index 6fb149a..dca101b 100644
--- a/material_maker/preview/preview_2d.tscn
+++ b/material_maker/preview/preview_2d.tscn
@@ -3,6 +3,7 @@
 [ext_resource path="res://material_maker/preview/preview_2d.gd" type="Script" id=1]
 
 [sub_resource type="Shader" id=1]
+resource_local_to_scene = true
 
 [sub_resource type="ShaderMaterial" id=2]
 resource_local_to_scene = true