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mphemphe
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Add example for attaching multiple ropes to a RigidBody
Also updates the rigidbody_rope_attachment example scene. Related to #34
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-24
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3 files changed

+164
-24
lines changed

‎demo/rope_examples/rigidbody_rope_attachment.tscn‎

Lines changed: 22 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -42,13 +42,27 @@ horizontal_alignment = 1
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[node name="Label" type="Label" parent="."]
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offset_left = 10.0
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offset_top = 451.0
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offset_right = 852.0
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offset_bottom = 630.0
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text = "Basic example on how to attach a RigidBody to a rope and enabling corresponding physics reactions.
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A PinJoint2D fixates the RigidBody to the rope.
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offset_top = 381.0
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offset_right = 1186.0
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offset_bottom = 638.0
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text = "A PinJoint2D fixates the RigidBody to the rope.
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As it only works on two physics bodies, a CharacterBody (rope_end) is used as proxy for the location on the rope.
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The softness property on the PointJoint2D can be tuned to make the RigidBodies less erratic on collisions.
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A RopeInteraction uses the RigidBody to control the rope and updates the PinJoint2D respectively.
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For this purpose, the RopeInteraction makes use of the input_override_node property."
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A RopeInteraction handles the mutual interaction between the RigidBody and the rope.
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It snaps the rope to the position indicated by the attachment_marker node and updates the rope_end+PinJoint2D to constrain the RigidBody to the rope.
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To specifically target the marker, the RopeInteraction makes use of the input_override_node property.
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The PinJoint2D, the rope_end and the attachment_marker nodes should be aligned initially, otherwise it may lead to undesired behavior.
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The disable_in_editor property of RopeInteraction is useful to prevent accidantelly messing up the layout."
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[node name="Label2" type="Label" parent="."]
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offset_left = 10.0
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offset_top = 8.0
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offset_right = 1146.0
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offset_bottom = 109.0
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text = "Basic example on how to attach a RigidBody to a rope and enabling corresponding physics reactions.
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Keep in mind that Godot's internal physics and the rope simulation of this plugin are completely different approaches.
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Combining them is a hack that will never produce perfect results and is not particularily intuitive."
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autowrap_mode = 3

‎demo/rope_examples/rigidbody_with_multiple_ropes.tscn‎

Lines changed: 122 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,122 @@
1+
[gd_scene load_steps=7 format=3 uid="uid://cioc6wtbs3ubf"]
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[ext_resource type="Script" uid="uid://b2shq2gjd4fvt" path="res://addons/ropesim/Rope.gd" id="1_mk4gc"]
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[ext_resource type="Script" uid="uid://y8nntt6dh711" path="res://rope_examples/scripts/character_body_2d.gd" id="1_ww34l"]
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[ext_resource type="Script" uid="uid://dvxegqp0cf77n" path="res://addons/ropesim/RopeInteraction.gd" id="2_ww34l"]
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[ext_resource type="Texture2D" uid="uid://criwv6nuivcxy" path="res://rope_examples/icon.svg" id="3_ovf25"]
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[sub_resource type="PhysicsMaterial" id="PhysicsMaterial_nwm6u"]
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[sub_resource type="RectangleShape2D" id="RectangleShape2D_3g7xa"]
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size = Vector2(64, 64)
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[node name="rope_with_body" type="Node2D"]
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position = Vector2(479, 16)
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[node name="left_rope_mover" type="CharacterBody2D" parent="."]
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position = Vector2(-176, 62)
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motion_mode = 1
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script = ExtResource("1_ww34l")
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[node name="Rope" type="Node2D" parent="left_rope_mover"]
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script = ExtResource("1_mk4gc")
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num_segments = 15
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rope_length = 250.0
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gravity = 61.765
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num_constraint_iterations = 20
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[node name="RopeInteraction" type="Node" parent="left_rope_mover/Rope" node_paths=PackedStringArray("target_node", "input_node_override", "rope")]
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script = ExtResource("2_ww34l")
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disable_in_editor = true
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position_update_mode = 0
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target_node = NodePath("../../../hanging_rigidbody/attach_marker/rope_end")
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input_node_override = NodePath("../../../hanging_rigidbody/attach_marker")
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rope = NodePath("..")
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[node name="Label" type="Label" parent="left_rope_mover"]
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offset_left = -24.0
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offset_top = -34.0
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offset_right = 23.0
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offset_bottom = -11.0
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text = "WSAD"
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[node name="right_rope_mover" type="CharacterBody2D" parent="."]
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position = Vector2(185, 80)
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motion_mode = 1
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script = ExtResource("1_ww34l")
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use_arrow_keys = true
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[node name="Rope2" type="Node2D" parent="right_rope_mover"]
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script = ExtResource("1_mk4gc")
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num_segments = 15
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rope_length = 250.0
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gravity = 61.765
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num_constraint_iterations = 20
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[node name="RopeInteraction" type="Node" parent="right_rope_mover/Rope2" node_paths=PackedStringArray("target_node", "input_node_override", "rope")]
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script = ExtResource("2_ww34l")
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disable_in_editor = true
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position_update_mode = 0
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target_node = NodePath("../../../hanging_rigidbody/attach_marker2/rope_end2")
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input_node_override = NodePath("../../../hanging_rigidbody/attach_marker2")
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rope = NodePath("..")
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[node name="Label" type="Label" parent="right_rope_mover"]
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offset_left = -24.0
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offset_top = -34.0
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offset_right = 23.0
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offset_bottom = -11.0
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text = "Arrow keys"
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[node name="hanging_rigidbody" type="RigidBody2D" parent="."]
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position = Vector2(-75, 156)
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mass = 20.091
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physics_material_override = SubResource("PhysicsMaterial_nwm6u")
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metadata/_edit_group_ = true
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[node name="attach_marker" type="Marker2D" parent="hanging_rigidbody"]
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position = Vector2(-19, 0)
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metadata/_edit_group_ = true
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[node name="rope_end" type="CharacterBody2D" parent="hanging_rigidbody/attach_marker"]
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collision_layer = 0
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collision_mask = 0
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motion_mode = 1
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[node name="PinJoint2D" type="PinJoint2D" parent="hanging_rigidbody/attach_marker/rope_end"]
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node_a = NodePath("../../..")
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node_b = NodePath("..")
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softness = 0.05
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[node name="attach_marker2" type="Marker2D" parent="hanging_rigidbody"]
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position = Vector2(22, 0)
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metadata/_edit_group_ = true
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[node name="rope_end2" type="CharacterBody2D" parent="hanging_rigidbody/attach_marker2"]
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collision_layer = 0
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collision_mask = 0
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motion_mode = 1
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[node name="PinJoint2D2" type="PinJoint2D" parent="hanging_rigidbody/attach_marker2/rope_end2"]
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node_a = NodePath("../../..")
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node_b = NodePath("..")
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softness = 0.05
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[node name="CollisionShape2D" type="CollisionShape2D" parent="hanging_rigidbody"]
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shape = SubResource("RectangleShape2D_3g7xa")
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[node name="Icon" type="Sprite2D" parent="hanging_rigidbody"]
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scale = Vector2(0.5, 0.5)
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texture = ExtResource("3_ovf25")
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[node name="Label" type="Label" parent="."]
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offset_left = -467.0
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offset_top = 466.0
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offset_right = 709.0
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offset_bottom = 619.0
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text = "Very similar setup to the \"rigidbody_rope_attachment\" example but with two ropes attached simultaneously.
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The same principles apply as before.
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As before, attaching Rigidbodies to ropes is a hack and will be tricky to make look right.
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For example, visible gaps will appear if both ropes are pulled away too far from each other.
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Additionally, ropes are not processed simultaneously. One rope will always be updated earlier, which can cause execution order related effects."

‎demo/rope_examples/scripts/rope_with_rigidbody.tscn‎

Lines changed: 20 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -19,26 +19,16 @@ rope_length = 250.0
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gravity = 75.0
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num_constraint_iterations = 20
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[node name="RopeInteraction" type="Node" parent="." node_paths=PackedStringArray("target_node", "input_node_override", "rope")]
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[node name="RopeInteraction" type="Node" parent="Rope" node_paths=PackedStringArray("target_node", "input_node_override", "rope")]
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script = ExtResource("2_1yts0")
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disable_in_editor = true
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position_update_mode = 0
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target_node = NodePath("../pin_point")
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input_node_override = NodePath("../hanging_rigidbody")
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rope = NodePath("../Rope")
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[node name="pin_point" type="CharacterBody2D" parent="."]
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position = Vector2(0, 250)
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collision_layer = 0
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collision_mask = 0
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motion_mode = 1
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[node name="PinJoint2D" type="PinJoint2D" parent="pin_point"]
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node_a = NodePath("../../hanging_rigidbody")
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node_b = NodePath("..")
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softness = 0.05
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target_node = NodePath("../../hanging_rigidbody/attachment_marker/rope_end")
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input_node_override = NodePath("../../hanging_rigidbody/attachment_marker")
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rope = NodePath("..")
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[node name="hanging_rigidbody" type="RigidBody2D" parent="."]
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position = Vector2(0, 250)
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position = Vector2(0, 281)
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mass = 5.0
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physics_material_override = SubResource("PhysicsMaterial_nwm6u")
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metadata/_edit_group_ = true
@@ -49,3 +39,17 @@ shape = SubResource("RectangleShape2D_3g7xa")
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[node name="Icon" type="Sprite2D" parent="hanging_rigidbody"]
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scale = Vector2(0.5, 0.5)
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texture = ExtResource("3_uwcl5")
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[node name="attachment_marker" type="Marker2D" parent="hanging_rigidbody"]
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position = Vector2(0, -31)
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metadata/_edit_group_ = true
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[node name="rope_end" type="CharacterBody2D" parent="hanging_rigidbody/attachment_marker"]
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collision_layer = 0
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collision_mask = 0
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motion_mode = 1
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[node name="PinJoint2D" type="PinJoint2D" parent="hanging_rigidbody/attachment_marker/rope_end"]
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node_a = NodePath("../../..")
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node_b = NodePath("..")
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softness = 0.05

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