Spatial Attitude is a Data Type representing an Object’s Position, Orientation and their velocities and accelerations.

Point of View is a Spatial Attitude that does not include velocity and acceleration.

Point is a geometric point in a Cartesian or Spherical Coordinate System.

Position is a representative Point of an Object a coordinate system.

Orientation is the set of 3 Euler angles of an Object.

Anchored Direction is represented by a line crossing a Point and having a direction determined by the line’s Azimuth (φ) and Elevation (θ) Angles.



Table 1provides the semantics of the components of the Spatial Attitude. Note that:

  1. Each of Position, Velocity, and Acceleration can be expressed in Cartesian (X,Y,Z) or Spherical (r,φ,θ) Coordinates.
  2. The Euler angles are indicated by (α,β,γ).

Table 1 – Components of the Object Spatial Attitude

HEADER 9 Bytes
·       Standard 7 Bytes The string OSD-OSA
·       Version 1 Byte Major version
·       Subversion 1 Byte Minor version
OSAID 16 Bytes UUID Identifier of Object Spatial Attitude.
·       CoordType bit 0 0: Cartesian, 1: Spherical
·       ObjectType bit 1-2 00: Digital Human
01: Generic
10 and 11: reserved
·       Precision bit 3 0: single precision; 1: double precision
·       MediaType bit 4-6 000: Audio; 001: Visual; 010: Haptic; 011: Smell; 100: RADAR; 101: LiDAR; 110: Ultrasound; 111: reserved
·       Reserved bit 6-7 reserved
·       SpatialAttitudeMask 2 Bytes 3*3 matrix of booleans (by rows)

Position Velocity Acceleration
Position and Orientation
·       CartPosition (X,Y,Z) 12/24 Bytes Array (in metres)
·       SpherPosition (r,φ,θ) 12/24 Bytes Array (in metres and degrees)
·       Orient (α,β,γ) 12/24 Bytes Array (in degrees)
Velocity of Position and Orientation
·       CartVelocity (X,Y,Z) 12/24 Bytes Array (in metres)
·       SpherVelocity (r,φ,θ) 12/24 Bytes Array (in metres and degrees)
·       OrientVelocity (α,β,γ) 12/24 Bytes Array (in degrees)
Acceleration of Position and Orientation
·       CartAccel (X,Y,Z) 12/24 Bytes Array (in metres)
·       SpherAccel (r,φ,θ) 12/24 Bytes Array (in metres and degrees)
·       OrientAccel (α,β,γ) 12/24 Bytes Array (in degrees)