In this lesson, you will learn how to use Chaos Physics Fields to influence dynamic objects in your game world without needing to manually apply forces to every individual actor.
The Power of Physics Fields
Instead of writing complex code to push objects around, you can use Physics Fields to create invisible zones that exert influence on any physics-enabled object within their bounds. Think of these as "area-of-effect" physics volumes. By placing a Field System Actor in your level, you can apply forces like Radial Falloff (to simulate explosions) or Uniform Vector (to simulate wind or gravity wells) to anything that intersects the field.
Setting Up a Field System
To get started, you need to use the Field System Actor. This actor acts as the container for your physics logic. Inside this actor, you define a Field System Component which contains the instructions for how the forces behave.
For example, to push objects away from a specific point like an explosion, you would use a Radial Falloff node. This defines the strength of the force based on the distance from the center. You then connect this to a Apply Physics Force function.
// Logic flow for a field effect
void AMyFieldActor::TriggerExplosion(FVector Origin, float Magnitude)
{
// You define the field parameters
URadialFalloff* Falloff = URadialFalloff::NewRadialFalloff(
Magnitude, 0.0f, Origin, Radius, FalloffType
);
// Then apply it to the Physics Field System
FieldSystemComponent->ApplyPhysicsField(EFieldPhysicsType::Field_LinearForce, Falloff);
}
Dynamic Interaction
The beauty of this system is that it handles the math for you. Whether you want to create a "zero-gravity" zone or a turbulent wind tunnel, you simply define the shape and the vector direction. Once a dynamic object enters that region, the Chaos solver automatically calculates the impact on that object's velocity. This is far more performance-efficient than checking for collisions manually every frame, as it leverages the underlying Chaos solver’s optimized simulation grid.
Key Takeaway: Physics Fields allow you to define persistent or transient zones of influence that automatically apply forces to rigid bodies, making dynamic environment interactions simple and scalable.