Body.component

Editable collider, mass, forces and complete velocity state on an ordinary Zero entity.

For static mesh collision, select shape=mesh, enable isStatic and assign a normal Zero mesh asset to mesh. meshScale sets the positive local collision scale; entity position/rotation place it in the world. Primitive sizes remain explicit. Changes to stored mesh geometry refresh collision automatically. No CPU-resident render copy or host files are required. Use the same mesh and corresponding scale for the visual Model when matching rendered and collision geometry. Meshes currently support up to8192 vertices/4096 triangles, static only; triangle winding determines the front face. Large-terrain acceleration remains unfinished.

collisionEnabled defaults to true. Disable it for an explicit animation/motor target or other noncolliding body. Mass, integration, joints and drives continue to work; only contact generation is disabled. This differs from collisionGroup, which suppresses pairs sharing the same nonzero group. The WASM state field is collision_enabled; omitted means true for existing saved states.

For shape="box", halfExtents describes the unrounded core and rounding adds the radius outside that core. An axis's total outer size is 2 * (halfExtents[axis] + rounding). The rounding radius may exceed the core's half-height (as it does for the stock deck). Core extents must be nonnegative, and every outer extent must be positive. These are the reconstructed engine's rounded-box conventions; rounding does not subtract from the entered core.

For shape="compound", add CollisionVolume components to direct child entities. Their local transforms and shape fields supply the ordered collision volumes; use unique integer orders. The Body's mass is the total compound mass. Changing child transforms or dimensions updates the submitted shape, and collision-disabled children retain their contribution to mass. Positive uniform body/child scales are supported. Position/rotation remain in the authored body frame while linear velocity describes its center of mass. Leave authoredMassFrame=false for normal compounds; true is an explicit source-specific override used by the stock deck.

maximumLinearVelocity and maximumAngularVelocity pass the native speed caps through to integration. Defaults remain1000000 for existing bodies; stock board construction carries its native unbounded/ wheel-specific values. Caps must be finite and nonnegative. solverOrder controls registration order within the World; entity ID breaks ties. Give assembly parts distinct orders when matching a source construction sequence. The same ordering field exists on Joint and Drive.

Enable customMassProperties to supply inverseMass, principal inverseInertia, and rotationalEnergyCoefficient explicitly. These replace inferred mass/inertia while retaining the selected collision geometry. All must be finite and positive; isStatic still suppresses inverse mass and inertia in the solver. With the switch off, existing geometry-derived behaviour remains unchanged.

massFramePosition and massFrameX/Y/Z/W describe the authored body frame in center-of-mass coordinates, using a unit quaternion. Entity transforms, collision geometry and Joint/Drive anchors remain in authored coordinates; linear velocity is the center-of-mass velocity. The kernel converts input/output poses and constraint frames consistently. This supports the reconstructed skeleton's independently adjusted inertia rather than forcing it into primitive estimates.

The JSON field is mass_properties: {inverse_mass, inverse_inertia, spherical, frame_position, frame_rotation}; omission preserves old behaviour. This is a body capability, not a completed native character preset or animation controller.

Native ground probes now include static boxes with positive half-extents. Rounding uses the original query fatness path. Solid box contacts remain native primitive-pair contacts, so a box does not need a TerrainQuery component; that component is for static triangle meshes. The visible Model and collision definition are independent. This does not add probe support for degenerate rounded boxes, static spheres or capsules.