usd-editor_skill

Overview

This skill guides safe, minimal edits to USD ASCII (.usda) files, focusing on preserving stage composition and authoring style. It helps you choose correct prim specifiers, update attributes, and validate paths and connections. Use it to make targeted changes while avoiding common USD pitfalls.

How this skill works

The skill inspects the stage structure to locate root prims, scopes, and exact SdfPaths you plan to edit. It recommends whether to use "over" for existing prims or "def" for new ones, and shows minimal edit patterns for attributes, relationships, transforms, variants, and list ops. It also suggests checks for xformOpOrder, timeSamples, and reference/variant composition so changes remain composition-safe.

When to use it

• Editing attribute values or relationship targets by hand in a .usda file
• Adding a small child prim or transform without altering composition arcs
• Fixing incorrect SdfPath targets or broken connections
• Making non-destructive overrides to existing prims
• Reviewing a .usda by hand before committing changes to a repo

Best practices

• Inspect stage and layer composition first; identify sublayers, references, and payloads before editing
• Prefer minimal edits: change attribute values or add a small over/def block instead of replacing sections
• Use 'over' for modifying existing prims and 'def' only for new prims or classes
• Update xformOpOrder whenever you add or remove xform ops to keep transform evaluation correct
• Validate SdfPath targets and types after edits to avoid invalid connections or type mismatches
• Avoid touching subLayers, references, or variants unless explicitly required

Example use cases

• Make an attribute value change (visibility, translate) using an over block to minimize diff noise
• Add a small Xform child with translate and corresponding xformOpOrder entry
• Bind a material relationship by setting rel material:binding to a valid SdfPath
• Fix a broken connection by correcting a relationship target path and verifying the target prim exists
• Inspect a stage with usdtree/usdcat guidance before performing manual edits