MPEG_mesh_linking
Contributors
- ISO/IEC SC29 WG3 (MPEG Systems) - Scene Description Breakout Group
- Contacts
- Thomas Stockhammer (MPEG-I Scene Description BoG Chair, tsto@qti.qualcomm.com)
Status
Based on ISO/IEC FDIS 23090-14
Dependencies
Written against the glTF 2.0 spec.
Overview
MPEG_mesh_linking extension provides the possibility to link a mesh to another mesh in a glTF asset. The shadow mesh corresponds to regular mesh data as defined by glTF 2.0 without the MPEG_mesh_linking extension. The dependent mesh can be transformed/animated by relying on the shadow mesh. The MPEG_mesh_linking extension included into the dependent mesh links the dependent mesh and the shadow mesh and provides with the data and information which is used to achieve the ability to animate the dependent mesh. Hence, the shadow mesh is present in the glTF assets to assist in achieving the ability to apply transformation onto the dependent mesh.
MPEG_mesh_linking Properties
| Type | Description | Required | |
|---|---|---|---|
| correspondence | integer | Provides a reference to the accessor | ✓ Yes |
| mesh | integer | Provides a reference to the shadow mesh | ✓ Yes |
| pose | integer | Provides a reference to the accessor | ✓ Yes |
| weights | integer | Provides a reference to the accessor | No |
| extensions | object | JSON object with extension-specific objects. | No |
| extras | any | Application-specific data. | No |
Additional properties are allowed.
- JSON schema: MPEG_mesh_linking.schema.json
MPEG_mesh_linking.correspondence
Provides a reference to the accessor, by specifying the accessor’s index in accessors array, that describe the buffer where the correspondence values between the dependent mesh and its associated shadow mesh will be made available. The componentType of the referenced accessor shall be as indicated in ISO/IEC 23090-14:7.4 and the type shall be SCALAR.
- Type:
integer - Required: ✓ Yes
- Minimum: ` >= 0`
MPEG_mesh_linking.mesh
Provides a reference to the shadow mesh, by specifying the mesh index in meshes array, associated to the dependent mesh for which the correspondence values are established.
- Type:
integer - Required: ✓ Yes
- Minimum: ` >= 0`
MPEG_mesh_linking.pose
Provides a reference to the accessor, by specifying the accessor’s index in accessors array, that describe the buffer where the transformation of the nodes associated to the dependent mesh will be made available. The componentType of the referenced accessor shall be FLOAT and the type shall be MAT4.
- Type:
integer - Required: ✓ Yes
- Minimum: ` >= 0`
MPEG_mesh_linking.weights
Provides a reference to the accessor, by specifying the accessor’s index in accessors array, that describe the buffer where the “weights” to be applied to the morph targets of the shadow mesh associated to the dependent mesh will be made available. The componentType of the referenced accessor shall be FLOAT and the type shall be SCALAR.
- Type:
integer - Required: No
- Minimum: ` >= 0`
MPEG_mesh_linking.extensions
JSON object with extension-specific objects.
- Type:
object - Required: No
- Type of each property: Extension
MPEG_mesh_linking.extras
Application-specific data.
- Type:
any - Required: No
Known Implementations
Resources
- ISO/IEC FDIS 23090-14, Information technology — Coded representation of immersive media — Part 14: Scene Description
- ISO/IEC WD 23090-24, Information technology — Coded representation of immersive media — Part 24: Conformance and Reference Software for Scene Description for MPEG Media
License
Copyright ISO/IEC 2022
The use of the “MPEG scene description extensions” is subject to the license as accessible here: https://standards.iso.org/ and is subject to the IPR policy as accessible here: https://www.iso.org/iso-standards-and-patents.html.