Rigid Body

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The Rigid Body Skeletal Control node (pictured below) can be used for light-weight physics simulation on characters using the high-performance Immediate Mode PhysX API. The Rigid Body node can be added to the AnimGraph of your Animation Blueprints and can even be used with any Blend Nodes enabling you to switch from a pose into a simulated physics state. Characters using this simulation can also generate collision with static geometry in the world.

RigidBodyNode.png

A typical use case for the Rigid Body node is on characters that have ponytails, chains, or other bones that "dangle" that you want to apply physics to.

Above, the hoses coming out of the character's head have a Physics Asset that is used with the Rigid Body node inside an Animation Blueprint.

Setup

Before using this node, inside your Physics Asset select and set the Physics Bodies you want to simulate to Simulated.

RigidBody_02.png

Above, we have set each of the bones associated with the hoses that come from the character's head to simulate physics.

With your Physics Asset set up, inside the AnimGraph of your Animation Blueprint, add the Rigid Body node and the necessary logic to define when to use it.

RigidBody_11.png

Above, we are taking in data from another Animation Blueprint and feeding it through the Rigid Body node before ending in our Final Animation Pose.

With the Rigid Body node selected in your AnimGraph, you can change properties that define how the node is used inside the Details panel.

RigidBody_12.png

Property

Description

Override Physics Asset

Physics asset to use. If empty, the Skeletal Mesh's default Physics Asset will be used.

Override World Gravity

Enables specification of a vector value to override gravity for this body.

External Force

Applies a uniform external force in world space. For example, this allows for easily faking inertia of movement while still simulating in component space.

Overlap Channel

The channel used to find static geometry to collide with.

Component Space Simulation

When true, simulation is done in component space. This means velocity is only inherited by animated bodies.

Cached Bounds Scale

Scale of cached bounds (versus actual bounds). Increasing this may improve performance, but overlaps may not work as well. A value of 1.0 effectively disables cached bounds.

(As Pin) Alpha

Shows the Alpha property as a pin on the node or in the Details panel.

Alpha Scale Bias

Set the Minimal and Maximal Influence values for the Alpha property.

perf.png

Property

Description

LOD Threshold

This is the max Level of Detail (LOD) that this node is permitted to run on. For example: if you have LOD Threshold set to 2, it will run until LOD 2, but disable itself once the component's LOD becomes 3.