1     Definition 2     Functional Requirements 3     Syntax
4     Semantics 5    Conformance Testing 6     Performance Assessment

1      Definition

An Item representing the Position and Orientation of an Object, and their velocities and accelerations.

2      Functional Requirements

  • The Position of an Object is that of a representative point in the Object.
  • Cartesian and Polar Coordinate Systems are supported.
  • The following media used types are supported: Audio; Visual; Audio-Visual; Haptic; Smell; RADAR; LiDAR; Ultrasound; Offline Map.
  • Error is the estimated absolute error in the measure of the value of each of CartPosition, SpherPosition, Orientation, CartVelocity, SpherVelocity, OrientVelocity, CartAccel, SpherAccel, OrientAccel.
  • Error is assumed to be the same for the three components of each value set.

3      Syntax

https://schemas.mpai.community/OSD/V1.2/data/SpatialAttitude.json

4      Semantics

Table 1 provides the semantics of the components of the Spatial Attitude. The following should be noted:

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

Table 1 – Semantics of the Spatial Attitude

Label Size Description
Header N1 Bytes Spatial Attitude Header
– Standard-SpatialAttitude 9 Bytes The characters “OSD-OSA-V”
– Version N2 Bytes Major version – 1 or 2 characters
– Dot-separator 1 Byte The character “.”
– Subversion N3 Bytes Minor version – 1 or 2 characters
MInstanceID N4 Bytes ID of Virtual Space Objectrefers to.
ObjectSpatialAttitudeID N5 Bytes  Identifier of Object Spatial Attitude.
General N6 Bytes Set of general data
– CoordinateType N7 Bytes One of Cartesian, Spherical, Geodesic, Toroidal.
– ObjectType N8 Bytes One of Digital Human, Generic.
– MediaType N9 Bytes One of Speech, Audio, Visual, Audio-Visual, Haptic, Smell, RADAR, LiDAR, Ultrasound.
– Precision N10 Bytes One of single precision, double precision
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)
Errors
– ErrCartPosition N11 Bytes Error of CartPosition
– ErrSpherPosition N12 Bytes Error of SpherPosition
– ErrOrientation N13 Bytes Error of Orientation
– ErrCartVelocity N14 Bytes Error of CartVelocity
– ErrSpherVelocity N15 Bytes Error of SpherVelocity
– ErrOrientVelocity N16 Bytes Error of OrientVelocity
– ErrCartAccel N17 Bytes Error of CartAccel
– ErrSpherAccel N18 Bytes Error of SpherAccel
– ErrOrientAccel N19 Bytes Error of OrientAccel
DescrMetadata N20 Bytes Descriptive Metadata

5     Conformance Testing

A Data instance Conforms with V1.2 Spatial Attitude V1.2 (OSD-OSA) if:

  1. The Data validates against the Spatial Attitude’s JSON Schema.
  2. All Data in the Spatial Attitude ’s JSON Schema have the specified type.

6     Performance Assessment