Physics Asset Editor in Unreal Engine - Skeleton Tree | Unreal Engine 5.7 Documentation

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The Skeleton Tree panel in the Physics Asset Editor shows the skeletal hierarchy of the current Skeleton asset, along with additional assets like the collision bodies, primitives, and constraints. Within it, you can perform the following actions:

Select and view specific bones in the skeletal hierarchy with their attached bodies and constraints.
Create and edit bodies, primitives, and constraints, which can be simulated in the Viewport to see the results of ragdoll animations, constraints, and collision interaction.
Create preview assets, which are temporarily attached assets; these are good for previewing how a weapon will look on a character, for example.

Interface Breakdown

Search Line

The Search line allows for quick filtering of the Skeletal hierarchy by filtering out the hierarchy to only include names based on the entered text.

Above, we have filtered the hierarchy to include any Bone Names, Bodies, or Constraints that include the text Pelvis in them.

Bone Hierarchy List

This window shows all the Bones, Bodies, Constraints, Primitives, and Preview Objects currently used by the selected Physics Asset. Inside this window is where you can add and assign collision Bodies, Primitives, Constraints, and Preview Objects. Most of the adjustments made in the Bone Hierarchy list are handled through right-click context menus where the menu options vary based on the object you right-click on (see the context menu sections below).

Selection Context Menus

Within the Bone Hierarchy list, when you right-click on a Bone, Body, Primitive, or Constraint, you access context menus specific to the selection made.

Below are the available context menus and their relative options.

Bone Context Menu

When right-clicking on a Bone, you will see the following context menu:

You will see the following context menu by clicking on the bone

Option	Description
Copy Selected Bone Names	Copy the selected bone names to the clipboard.
Reset Selected Bone Transforms	Reset the transforms of the selected bones.
Add Preview Asset	Opens a menu of all eligible assets that can be temporarily attached to a bone for previewing purposes. For instance, if you want to see what a certain piece of armor would look like attached to a bone, this is the option you would use. Note, however, that this is not a permanent attachment and will only be visible while previewing.
Remove All Attached Assets	Removes all attached assets from the Skeleton and the mesh.
Add/Replace Bodies	Adds or replaces bodies for the selected bones using the current generation settings found in the Tools tab.
Add Shape	Adds shapes to the body.
Select All Bodies	Selects all bodies in the Skeleton Tree.
Select Simulated Bodies	Selects all simulated bodies in the Skeleton Tree.
Select Kinematic Bodies	Selects all kinematic bodies in the Skeleton Tree.
Select All Constraints	Selects all constraints in the Skeleton Tree.

Body Context Menu

When right-clicking on a Body, you will see the following context menu:

You will see the following context menu by clicking on the body

Option	Description
Regenerate Bodies	Regenerates the selected bodies using the current generation settings found in the Tools tab.
Add Shape	Adds shapes to this body. A Box, Sphere, or Capsule shape can be selected.
Collision	Adjust collision between bodies. Weld: Weld the currently selected bodies together. Enable Collision: Enable collision between the currently selected bodies. Enable Collision All: Enable collision between the currently selected bodies and all bodies. Disable Collision: Disable collision between the currently selected bodies. Disable Collision All: Disable collision between the currently selected bodies and all bodies.
Constraint selected bodies	Create a constraint between all selected bodies as children and the last selected body as parent.
Constraints	Create a constraint between the selected body and one selected from the hierarchy list.
Physics Type	The type of physics to use for this body; kinematic or simulated.
Physical Material	Select a Physical Material to apply to all bodies.
Copy Selected Bodies/Constraints To Clipboard	Copy the bodies/constraints of the currently selected object to clipboard.
Paste Bodies/Constraints From Clipboard	Paste the previously selected bodies/constraints from clipboard.
Copy Properties	Copy the properties of the currently selected object to the next selected object.
Paste Properties	Past the properties of a previously selected object to the currently selected object.
Delete	Delete the currently selected body.
Delete All Bodies Below	Delete all bodies below the currently selected body in the Skeleton Hierarchy Tree.
Mirror	Find the body on the other side and duplicate its constraints and body.
Assign	Assigns the selected bodies to the current physical animation profile.
Unassign	Unassigns the selected bodies from the current physical animation profile.
Copy Collision From Static Mesh	Copy convex collision from a specified Static Mesh.
Select All Bodies	Selects all bodies in the Skeleton Tree.
Select Simulated Bodies	Selects all simulated bodies in the Skeleton Tree.
Select Kinematic Bodies	Selects all kinematic bodies in the Skeleton Tree.
Select All Constraints	Selects all constraints in the Skeleton Tree.

Primitive Context Menu

When right-clicking on a Primitive, you will see the following context menu:

You will see the following context menu by clicking on the primitive

Option	Description
Rename	Rename selected primitives.
Duplicate	Duplicate selected primitives.
Delete	Delete selected primitives.
Select All Bodies	Selects all bodies in the Skeleton Tree.
Select Simulated Bodies	Selects all simulated bodies in the Skeleton Tree.
Select Kinematic Bodies	Selects all kinematic bodies in the Skeleton Tree.
Select All Constraints	Selects all constraints in the Skeleton Tree.

Constraint Context Menu

When right-clicking on a Constraint, you will see the following context menu:

You will see the following context menu by clicking on the constraint

Option	Description
Snap	Snap the selected constraint to Bone.
Reset	Resets the constraint to the default state.
Axes and Limits	Edit axes and limits of this constraint. Cycle Constraint Orientation: Cycles constraint orientation between different cardinal axes. Cycle Active Constraint: Cycles whether each constraint axis is active in isolation. Lock Swing: Set swings 1 or 2 to be locked or limited. Lock Twist: Set twist to be locked or limited.
Convert	Convert constraint to various presets. Ball & Socket Hinge Prismatic Skeletal
Copy Selected Bodies/Constraints To Clipboard	Copy the bodies/constraints of the currently selected object to clipboard.
Paste Bodies/Constraints From Clipboard	Paste the previously selected bodies/constraints from clipboard.
Copy Properties	Copy the properties of the currently selected object to the next selected object.
Paste Properties	Past the properties of a previously selected object to the currently selected object.
Delete	Delete the currently selected constraint.
Assign	Assigns the selected constraints to the current physical animation profile.
Unassign	Unassigns the selected constraints from the current physical animation profile.
Copy Collision From Static Mesh	Copy convex collision from a specified Static Mesh.
Select All Bodies	Selects all bodies in the Skeleton Tree.
Select Simulated Bodies	Selects all simulated bodies in the Skeleton Tree.
Select Kinematic Bodies	Selects all kinematic bodies in the Skeleton Tree.
Select All Constraints	Selects all constraints in the Skeleton Tree.

Preview Asset Context Menu

A Preview Asset is an asset, such as a Static Mesh or Skeletal Mesh, that has been temporarily attached to a bone or socket for previewing purposes.

When right-clicking on a Preview Asset, you will see the following context menu:

You will see the following context menu by clicking

Option	Description
Add Preview Asset	Opens a menu of all eligible assets that can be temporarily attached to a bone for previewing purposes. For instance, if you want to see what a certain piece of armor would look like attached to a bone, this is the option you would use. Note, however, that this is not a permanent attachment and will only be visible while previewing.
Remove All Attached Assets	Deletes all Preview Assets currently on the mesh.

Skeleton Show/Hide Options

The Skeleton Options window enables you to show or hide Bones, Bodies, Constraints, and Primitives.

The Skeleton Options window enables you to show or hide Bones Bodies Cinstraints and Primitives

Option	Description
UpperBodyMask	Selects the blend profile for editing.
LowerBodyMask	Selects the blend profile for editing.
FastFeet	Selects the blend profile for editing.
LeftFingersMask	Selects the blend profile for editing.
UpperBodyLowerBodySplitMask	Selects the blend profile for editing.
Clear	Clears the selected blend profile.
Add Time Blend Profile	Adds a new time blend profile for this skeleton.
Add Weight Blend Profile	Adds a new weight profile for the skeleton.
Add Blend Mask	Adds a new blend mask for the skeleton.
Filtering Flattens Hierarchy	Whether to keep the hierarchy or flatten it when searching for tree items.
Hide Parents When Filtering	Whether to show parent items grayed out or hide them entirely when filtering.
Show Bodies	Display bodies in the tree view. Bodies are a collection of primitive shapes used for collision.
Show Simulated Bodies	Show all simulated bodies in the Skeleton Tree.
Show Kinematic Bodies	Show all kinematic bodies in the Skeleton Tree.
Show Constraints	Display constraints in the tree view. Constraints are used to control how bodies can move in to one another.
Show Primitives	Display primitive shapes (spheres, boxes, capsules, etc.) in the tree view.
Show Constraints on Parent Body	Display constraints on both the parent and child body.
Show All Bones	Show every bone in the skeleton.
Show Mesh Bones	Show bones that are used in the mesh.
Show LOD Bones	Show bones that are used in the LOD (level of detail) being displayed.
Show Weighted Bones	Show bones that have vertices weighted to them.
Hide Bones	Hide all bones (sockets and attached assets will still be listed).