2. IDL Profiles

The SpatialDDS IDL bundle defines the schemas used to exchange real-world spatial data over DDS. It is organized into complementary profiles: Core, which provides the backbone for pose graphs, geometry, and geo-anchoring; Discovery, which enables lightweight announcements of services, coverage, anchors, and content; and Anchors, which adds support for publishing and updating sets of durable world-locked anchors. Together, these profiles give devices, services, and applications a common language for building, sharing, and aligning live world models—while staying codec-agnostic, forward-compatible, and simple enough to extend for domains such as robotics, AR/XR, IoT, and smart cities.

2.1 Core SpatialDDS

The Core profile defines the essential building blocks for representing and sharing a live world model over DDS. It focuses on a small, stable set of concepts: pose graphs, 3D geometry tiles, blob transport for large payloads, and geo-anchoring primitives such as anchors, transforms, and simple GeoPoses. The design is deliberately lightweight and codec-agnostic: tiles reference payloads but do not dictate mesh formats, and anchors define stable points without tying clients to a specific localization method. All quaternion fields follow the OGC GeoPose component order (x, y, z, w) so orientation data can flow between GeoPose-aware systems without reordering. By centering on graph + geometry + anchoring, the Core profile provides a neutral foundation that can support diverse pipelines across robotics, AR, IoT, and smart city contexts.

2.2 Discovery

The Discovery profile adds a minimal, lightweight way to announce services, anchors, content, and registries in the real world. It complements DDS’s built-in participant and topic discovery by describing what a service does, where it operates, and how to learn more. Announcements are deliberately simple—service kind, coarse coverage (via geohash or a bounding-box array [min_lon, min_lat, max_lon, max_lat]), and a pointer to a manifest for richer details. This keeps the bus lean while enabling clients to discover and connect to services such as VPS, mapping, anchor registries, semantics, or AR content providers without requiring heavy registries or complex protocols.

2.3 Anchors

The Anchors profile provides a structured way to share and update collections of durable, world-locked anchors. While Core includes individual GeoAnchor messages, this profile introduces constructs such as AnchorSet for publishing bundles (e.g., a venue’s anchor pack) and AnchorDelta for lightweight updates. This makes it easy for clients to fetch a set of anchors on startup, stay synchronized through incremental changes, and request full snapshots when needed. Anchors complement VPS results by providing the persistent landmarks that make AR content and multi-device alignment stable across sessions and users.

2.4 Profiles Summary

The complete SpatialDDS IDL bundle is organized into the following profiles:

  • Core Profile
    Fundamental building blocks: pose graphs, geometry tiles, anchors, transforms, and blob transport.
  • Discovery Profile
    Lightweight announce messages and manifests for services, coverage areas, anchors, and spatial content or experiences.
  • Anchors Profile
    Durable anchors and the Anchor Registry, enabling persistent world-locked reference points.

Together, Core, Discovery, and Anchors form the foundation of SpatialDDS, providing the minimal set required for interoperability.

  • Extensions
  • VIO Profile: Raw and fused IMU and magnetometer samples for visual-inertial pipelines.
  • SLAM Frontend Profile: Features, descriptors, and keyframes for SLAM and SfM pipelines.
  • Semantics Profile: 2D and 3D detections for AR occlusion, robotics perception, and analytics.
  • AR+Geo Profile: GeoPose, frame transforms, and geo-anchoring structures for global alignment and persistent AR content.
  • Provisional Extensions (Optional)
  • Neural Profile: Metadata for neural fields (e.g., NeRFs, Gaussian splats) and optional view-synthesis requests.
  • Agent Profile: Generic task and status messages for AI agents and planners.

Together, these profiles give SpatialDDS the flexibility to support robotics, AR/XR, digital twins, IoT, and AI world models—while ensuring that the wire format remains lightweight, codec-agnostic, and forward-compatible.