use ;
use Validate;
/// A node in the node hierarchy. When the node contains `skin`, all
/// `mesh.primitives` must contain `JOINTS_0` and `WEIGHTS_0` attributes.
/// A node can have either a `matrix` or any combination of
/// `translation`/`rotation`/`scale` (TRS) properties. TRS properties are converted
/// to matrices and postmultiplied in the `T * R * S` order to compose the
/// transformation matrix; first the scale is applied to the vertices, then the
/// rotation, and then the translation. If none are provided, the transform is the
/// identity. When a node is targeted for animation (referenced by an
/// animation.channel.target), only TRS properties may be present; `matrix` will not
/// be present.
/// The root `Node`s of a scene.