Sets the rotation of the specified object using a quaternion. Alternatively you can use SetObjectRotation to use Euler angles. By default objects are created with the quaternion 1,0,0,0 in the order w,x,y,z. A Quaternion is a 4 dimensional representation of a 3D rotation with the property w^2+x^2+y^2+z^2 = 1 which allows easy interpolation between two rotations by linearly interpolating the two quaternions and normalising them. Each 3D rotation is represented by exactly 2 quaternions, w,x,y,z and -w,-x,-y,-z so either version may be returned by the GetObjectQuat commands. Quaternions and Euler angles can both be used at the same time. For example setting a quaternion rotation will generate equivalent Euler values that can be retrieved with GetObjectAngleX, GetObjectAngleX, and GetObjectAngleZ.
SetObjectRotationQuat( objID, w, x, y, z )