StaticBodyBuilder

StaticBodyBuilder adds PhysicsBodyComponent and PhysicsBodyUpdateComponent for a static body — fixed geometry that either pushes dynamics (rigid) or records overlaps (trigger). Runtime equivalent of StaticBodyAuthoring.

Static bodies support sphere and capsule only. They are registered in the spatial map once (TimeElapsed = -1), unlike kinematic or dynamic bodies.

Required chaining

StaticBodyBuilder has no parameterless constructor with baked defaults. Always chain at least:

.WithCollider(...) — shape and size
.AsRigidBody(...) or .AsTrigger() — mode and material

Calling Build without WithCollider leaves ColliderScale at 0. Calling Build without AsRigidBody / AsTrigger leaves IsTrigger = false with zero material values.

Fluent methods

Method	Description
`.WithCollider(StaticBodyAuthoring.ColliderType colliderType, float colliderScale, float3 colliderLocalPosition = default)`	Sphere or capsule shape, scale, and local offset
`.AsRigidBody(float bounciness, float friction, float hardness)`	Rigid static — pushes dynamics when dynamics or kinematics pair against it
`.AsTrigger()`	Trigger static — overlap data only, no push-out

There is no update interval on static triggers — static bodies are placed once in StaticMap. Dynamic and kinematic bodies initiate overlap tests when they query those cells.

Build

public void Build(EntityCommandBuffer commandBuffer, Entity entity)

Sets PhysicsBodyComponent.Main to entity. Layer defaults to 0.

Examples

Runtime wall (capsule rigid):

using LittlePhysics;
using Unity.Entities;
using Unity.Mathematics;

new StaticBodyBuilder()
    .WithCollider(
        StaticBodyAuthoring.ColliderType.Capsule,
        colliderScale: 1.5f,
        colliderLocalPosition: new float3(0f, 1f, 0f))
    .AsRigidBody(bounciness: 0f, friction: 0.5f, hardness: 1f)
    .Build(commandBuffer, entity);

Pickup zone (sphere trigger):

new StaticBodyBuilder()
    .WithCollider(StaticBodyAuthoring.ColliderType.Sphere, colliderScale: 2f)
    .AsTrigger()
    .Build(commandBuffer, entity);

Ensure the entity has a LocalTransform at the final world pose before import — static bodies do not move after map insertion.

Components written

Component	Rigid	Trigger
`PhysicsBodyComponent`	`BodyType.Static`, `IsTrigger = false`, shape + material	`IsTrigger = true`
`PhysicsBodyUpdateComponent.TimeElapsed`	`-1` (insert once)	`-1`
`PhysicsBodyUpdateComponent.Interval`	`0`	`0`

Statics are not tested against surfaces in the built-in surface pass. For large ground planes, prefer a baked surface body.

Static vs kinematic at runtime

Need	Builder
Fixed collider, never moves	`StaticBodyBuilder`
Moves every frame (platform, door)	`KinematicBodyBuilder`
Moving overlap volume	`KinematicBodyBuilder` with `.AsTrigger`