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lula-description-generator

Generate Lula collision sphere descriptions from URDF files for Isaac Sim.

7|1|Updated Mar 13, 2026
Search Tags:#urdf#isaac-sim#robot-description#lula#collision-spheres#mesh-repair
One-click install
npx skills add https://github.com/hkqai/MatClaw --skill lula-description-generator
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: lula-description-generator
Source: https://github.com/hkqai/MatClaw/tree/main/skills/lula-description-generator
Command: npx skills add https://github.com/hkqai/MatClaw --skill lula-description-generator

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Manually creating collision sphere approximations for robot links is time‑consuming and error‑prone; this Skill automates the generation of those spheres directly from a URDF, producing a ready‑to‑use Lula robot description for Isaac Sim.

Core Features & Use Cases

  • Automated mesh repair using pymeshfix with a trimesh fallback, ensuring non‑watertight meshes can be processed.
  • Voxel‑based interior analysis followed by Euclidean distance transforms to capture geometry detail.
  • Greedy medial‑axis sphere packing that yields a set of collision spheres per link, customizable via parameters such as max_spheres_per_link and voxel_fraction.
  • Full YAML robot description output compatible with Isaac Sim’s CuMotion/RMPflow/Lula planners, supporting package:// URI resolution and optional c‑space configuration.
  • Use case: Researchers can feed any robot URDF into the skill to instantly obtain a collision‑aware description, accelerating simulation setup and motion‑planning experiments.

Quick Start

Run the lula description generator on my_robot.urdf to obtain a Lula description YAML file.

Frequently Asked Questions about lula-description-generator

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I generate collision spheres for a URDF robot model in Isaac Sim?▼

You can generate collision spheres from a URDF file by processing meshes, repairing geometry, voxelizing interiors, and packing spheres to produce a Lula robot description YAML for Isaac Sim motion planning.

What is the best way to create a Lula robot description YAML from a URDF file?▼

Creating a Lula robot description YAML from a URDF file is best automated through mesh repair, voxel-based interior analysis, and greedy medial-axis sphere packing to approximate link geometries for motion planners.

How does voxelization and mesh repair work for URDF collision sphere generation?▼

Mesh repair uses pymeshfix with a trimesh fallback to resolve non-watertight geometry, while voxelization applies Euclidean distance transforms to capture interior detail for accurate medial-axis collision sphere packing.

Can I control the number of collision spheres generated per robot link?▼

You can control collision spheres per link by adjusting parameters like max_spheres_per_link and voxel_fraction, which regulate sphere packing granularity to balance collision checking precision with computational performance.

Does the Lula description generator require watertight meshes to process URDF files?▼

Watertight meshes are not required because the generator applies automated mesh repair using pymeshfix and a trimesh fallback to fix non-watertight geometry before voxelizing interiors and packing collision spheres.

Why do I need collision spheres for Isaac Sim motion planning workflows?▼

Collision spheres are needed for Isaac Sim motion planning workflows because they provide a simplified geometric approximation of robot links, enabling efficient collision-aware path planning with CuMotion, RMPflow, and Lula planners.

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