rigid_body_position

The position of a rigid-body represents its location (translation) in 2D or 3D world-space, as well as its orientation (rotation). stored in the standard Bevy Transform component.

The position of a rigid-body can be set when creating it. It can also be set after its creation as illustrated below.

warning

Directly changing the position of a rigid-body is equivalent to teleporting it: this is a not a physically realistic action! Teleporting a dynamic or kinematic bodies may result in odd behaviors especially if it teleports into a space occupied by other objects. For dynamic bodies, forces, impulses, or velocity modification should be preferred. For kinematic bodies, see the discussion after the examples below.

Example 2D

commands
    .spawn(RigidBody::Dynamic)
    .insert(TransformBundle::from(Transform::from_xyz(0.0, 5.0, 0.0)))

/* Change the position inside of a system. */
fn modify_body_translation(mut positions: Query<&mut Transform, With<RigidBody>>) {
    for mut position in positions.iter_mut() {
        position.translation.y += 0.1;
    }
}

Example 3D

commands
    .spawn(RigidBody::Dynamic)
    .insert(TransformBundle::from(Transform::from_xyz(0.0, 0.0, 0.0)))

/* Change the position inside of a system. */
fn modify_body_translation(mut positions: Query<&mut Transform, With<RigidBody>>) {
    for mut position in positions.iter_mut() {
        position.translation.y += 0.1;
    }
}

In order to move a dynamic rigid-body it is strongly discouraged to set its position directly as it may results in weird behaviors: it's as if the rigid-body teleports itself, which is a non-physical behavior. For dynamic bodies, it is recommended to either set its velocity or to apply forces or impulses.

For velocity-based kinematic bodies, it is recommended to set its velocity instead of setting its position directly. For position-based kinematic bodies, it is recommended to modify its Transform (changing its velocity won’t have any effect). This will let the physics engine compute the fictitious velocity of the kinematic body for more realistic intersections with other rigid-bodies.