DEVELOPERS · IMPORT USD

TOOLCHAIN 0.1.1 · WORKING ALPHA

A narrow USDA importer is safer than a fake full USD engine.

The current importer accepts UTF-8 text USDA, including text .usd files beginning with #usda, and extracts a deliberately restricted subset of authored UsdPhysics joint evidence.

IMPLEMENTATION BOUNDARY

Text USDA is implemented and lifecycle-tested for a narrow subset. Binary USD/USDC is not supported. The parser does not perform layer composition, reference/payload resolution, variant evaluation or full OpenUSD SDK semantics.

COMMAND

Import text USDA evidence.

USDA importshell
rgd import robot.usda --out partial-robot

PARSER PROFILE

The current subset is intentionally auditable.

01

Stage metadata

defaultPrim, metersPerUnit, kilogramsPerUnit and upAxis when authored.

02

Joint schemas

PhysicsRevoluteJoint and PhysicsPrismaticJoint.

03

Body relations

physics:body0 and physics:body1 are preserved as source relationships.

04

Axes + limits

X/Y/Z axes and authored lower/upper limits.

05

Local frames

Directly authored local joint frames when present.

06

Drives

Authored maxForce, stiffness and damping for supported angular/linear drives.

UNIT CONVERSION

Convert only when authored metadata justifies it.

conversion rulesshell
revolute position   degrees → radians
prismatic position  stage distance × metersPerUnit → metres
linear maxForce      requires metersPerUnit + kilogramsPerUnit
angular maxForce     requires metersPerUnit + kilogramsPerUnit

Raw source values remain available in source_usd_joint_map. Missing required unit metadata is not silently replaced.

NOT SUPPORTED

Use a full OpenUSD adapter when composition matters.

The lightweight parser does not compose layers, resolve references or payloads, evaluate variants, resolve inherited opinions, evaluate complete transform stacks or comprehensively implement schema fallback behavior.

BINARY USD

USDC is outside the current importer.

Binary USD/USDC is not supported by this parser. Convert to USDA for the current path or use a future full OpenUSD SDK adapter.

RELATED GUIDES

Continue through the verified toolchain.

CANONICAL SOURCE