# CollisionVolume Put this component on a direct child of a Body whose shape is `compound`. Edit the child's local position and rotation with Zero's normal transform tools. Positive uniform scale on the body and child is included in collision dimensions; nonuniform/mirrored scale is rejected. Shape fields define sphere, rounded-box core, Z-axis capsule, or triangle geometry. Triangle transforms are baked into vertices when the Body reads its state, preserving native mass conventions. Give each child a unique integer `order`. It preserves the authored accumulation order independently of entity IDs. `collisionEnabled=false` suppresses contacts but retains mass. Delete a child to remove both its geometry and mass contribution. The Body supplies material and total mass. It may have at most64 volume children. Use `API.attachVolume(child, settings)` to attach this component and automatically choose the next free order; the child's parent must already be a compound Body. All properties and transforms are ordinary synchronized Zero entity data. ## Native actor bodies CollisionVolume can also be a direct child of a NativeActorPart with role=board or role=rider. One or more volume children replace that body's native contact geometry; parts without volume children inherit their defaults. Removing the last child restores the defaults. Disabled children suppress contacts; use a disabled child when the intent is no contacts rather than inherited defaults. Child local transforms are in the body entity's centre-of-mass frame. No host files are needed. For native bodies, geometry editing does NOT recalculate mass or inertia: those remain separate NativeActorPart fields. It also does not alter the animation or wheel-probe/controller profile. Materials and controller collision gating stay native. Rider shapes retain native mode-dependent enable flags, collision groups and materials. A shape cannot enable a body the current native mode disables. The ready NativeRiderDriver:readColliderDefinitions() method reads current body-local native geometry, including disabled children, for inspection or in-engine authoring. Spheres were checked with actual Zero physical response, reset and restoration. Rounded boxes, capsules with offsets/rotation, and two triangle volumes were also checked against their calculated support height. Disabling the triangles removed their support; deleting them restored all 15 default deck children. Rider sphere authoring, disable/reset/restore and native masking have been checked. Additional rider multi-volume/self-contact scenarios remain to verify. The ready driver readRiderColliderDefinitions() method returns each rider body with its current native enabled flag, volume_group, and body-local shapes. Vehicle-only mode returns an empty rider list and rejects rider shape input.

# 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.