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URDF VS RGD

Robot structure and semantic embodiment are complementary layers.

URDF is strong at describing links, joints and physical robot structure. RGD consumes source-supported body evidence and adds identity, provenance, operational constraints, capability semantics and lifecycle context.

URDF+RGD
CITATION RECORDCanonical source ↗
MATURITYREFERENCE COMPARISON
LAST VERIFIED22 Sep 2026
SOURCE VERSIONROS URDF documentation + OpenRGD Import Guide / Runtime Boundary
EVIDENCE BOUNDARYComplementary-layer comparison; not a winner/loser ranking and not a claim that RGD replaces URDF.

RESPONSIBILITY MATRIX

Different centers of gravity.

DIMENSIONURDFRGD
Primary responsibility

Robot model structure for ROS-centric tooling.

Semantic embodiment and machine-readable grounding context.

Core representation

XML links, joints and related physical/model properties.

Modular graph/profile across explicit semantic domains.

Kinematics

First-class: topology, axes, joint types and limits.

Can preserve/import kinematic evidence inside Foundation.

Identity

Robot model name and file/model identity.

Canonical profile identity, manifests and integrity commitments.

Operational semantics

Mostly outside the core format responsibility.

Operation domain for runtime constraints and safety context.

Capabilities

Usually expressed elsewhere in the stack.

Agency domain for declared capability and action semantics.

Provenance

Not a central cross-domain provenance model.

Source evidence and derivation boundaries are explicit.

Actuation

URDF itself does not authorize hardware execution.

RGD also does not authorize hardware execution.

OVERLAP

Where both may describe the same robot facts.

  • Link and joint topology.
  • Joint types, axes and source-authored limits.
  • Inertial mass and inertia when present.
  • Dynamics and mimic relationships when supported by the source.
  • Names and structural relationships used to identify body elements.

WHAT RGD ADDS

Context beyond the source description.

  • Canonical source-tree identity and integrity verification.
  • Separation between imported evidence and later enrichment.
  • Operational envelopes and machine-readable safety context.
  • Declared capabilities and action semantics.
  • Lifecycle, adaptation and continuity context.
  • Explicit boundary between cognition, planning and physical execution.

RGD DOES NOT REPLACE

Keep ownership explicit.

  • URDF-based ROS robot-model workflows.
  • robot_state_publisher and tooling that expects URDF.
  • Mesh/geometry asset handling already expressed through the URDF ecosystem.
  • ROS middleware or ros2_control.
  • A hardware driver or embodied runtime.

USE BOTH WHEN

Complementary layers are stronger than forced convergence.

  • You already maintain a URDF as the canonical structural robot model.
  • AI or planning systems need body context beyond links and joints.
  • You want to preserve exact source provenance instead of manually copying facts.
  • You need to distinguish source evidence from safety/capability enrichment.
  • You want deterministic static exports while keeping runtime ownership downstream.

OPENRGD FLOW

Source evidence can become semantic context without erasing provenance.

01URDF source→
02rgd import→
03Partial Foundation evidence→
04Explicit enrichment→
05rgd check / boot→
06Downstream runtime

PRIMARY SOURCES

01ROS 2 — URDF documentation↗02ROS — urdf package documentation↗03OpenRGD — Import Guide↗04OpenRGD — Runtime Boundary↗
← All description formatsRGD reference →