SphereCollider

Description

The SphereCollider class implements a spherical collision volume for physics interactions. It’s useful for simple objects, characters, or trigger areas that can be approximated with a sphere shape. Sphere colliders are computationally efficient and provide smooth collision responses.

Namespace

Universe.Core

Properties

Property	Type	Description
trigger	bool	When true, the collider acts as a trigger that detects overlaps but doesn’t create physical collisions
center	vector3	The local center position offset of the sphere collider
radius	float	The radius of the sphere (default: 0.5)
attitude	Attitude	The physical material properties of the collider (affects bounce, friction, etc.)

Methods

OnInit

void OnInit()

Called when the script initializes. Registers the sphere collider with the physics system.

Example Usage

// Create a basic sphere collider for a ball
SphereCollider ballCollider = new SphereCollider();
ballCollider.radius = 0.25; // 25cm radius
ballCollider.trigger = false; // Solid physical collider
ballCollider.attitude = Attitude.HighBouncing; // Bouncy material

// Create a larger trigger area for detection
SphereCollider detectionZone = new SphereCollider();
detectionZone.radius = 5; // 5 meter detection radius
detectionZone.center = [0, 1, 0]; // Centered 1 meter above the object's origin
detectionZone.trigger = true; // Just for overlap detection

// Create a character collider
SphereCollider characterCollider = new SphereCollider();
characterCollider.radius = 0.5; // Body radius
characterCollider.center = [0, 1, 0]; // Centered at character's middle
characterCollider.attitude = Attitude.SemiAbsorbing; // Some bounce absorption

Technical Details

• A sphere collider is defined by a center point and a radius
• The center is specified in local coordinates relative to the object’s position
• Sphere colliders are the simplest and most efficient 3D collision shape
• They provide consistent collision response from all directions
• When trigger is true, collisions will generate trigger events but won’t cause physical reactions
• The attitude property affects physical properties like bounciness

Use Cases

• Simple rounded objects like balls, projectiles, or gems
• Character colliders for basic collision detection
• Trigger zones for ability effects, sound triggers, or detection areas
• Approximating simple objects for better performance
• Smooth-rolling objects that need consistent collision behavior
• Particle collision in physics simulations

Notes

• For character colliders, consider using CapsuleCollider which better fits humanoid shapes
• Sphere colliders are very efficient for performance, so prefer them for simple objects
• For complex shapes, consider using multiple sphere colliders or switch to mesh colliders
• The sphere’s radius affects both the collision detection and physics behavior
• For most accurate results, position the center at the object’s visual center

Related Components

• Alternative to BoxCollider.cs, CapsuleCollider.cs, and MeshCollider.cs
• Works with Physics.cs for physical interactions

Dependencies

• Uses ColliderUtil.AddSphereCollider() to register with the physics system