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Tutorial 2: Inspect asset#

Tutorial

You have seen how the Inspire Hand is built from multiple USD files. Now inspect and validate its joints and collision meshes. Incorrect collider types or misaligned collision geometry can slow the simulation and produce confusing contact behavior. The joint visualizer, Robot Inspector, and collider visualization let you assess the asset before filtering collision pairs or tuning drives.

Learning Objectives#

In this tutorial, you will:

  • Enable the joint visualizer and interpret Fixed, Revolute, and Mimic joints.

  • Use Robot Inspector to review the hand’s kinematic chain.

  • Enable collider visualization and verify collider approximations.

Prerequisites#

Enable the joint visualizer#

Because this series tunes the PhysX backend, load the hand with the PhysX variant before you inspect its joints.

Viewport navigation#

  • Orbit: Hold Alt and the left mouse button, then drag.

  • Look around: Hold the right mouse button and move the mouse.

  • Zoom: Hold Alt and the right mouse button, or use the scroll wheel.

  • Pan: Hold the middle mouse button and drag.

  • Focus a prim: Select the prim in the Stage panel and press F.

  1. Select the top-level inspire_hand prim.

  2. In the Property panel, expand Variants and select PhysX.

Property panel with the PhysX variant selected.

  1. Go to Eye > Show by Type > Physics > Joints.

Menu path that enables joint visualization.

The viewport displays a gizmo at each joint.

Inspire Hand viewport with joint visualization enabled.

Read the visualization#

  • Gizmos identify joint locations. Their icon shapes indicate joint type.

  • Lines between joints show the kinematic chain and parent-to-child direction.

  • A circle appears when multiple joints overlap on screen. Click it to select one of those joints.

In the Stage panel, under /Physics, locate the following index-finger joints:

  • right_index_1_joint is a Revolute joint that drives the base motion of the index finger.

  • right_index_rubber_1_joint is a Fixed joint that attaches the lower rubber pad to its link.

  • right_index_2_joint is a Mimic joint that copies right_index_1_joint motion.

Robot Inspector#

The Robot Inspector window shows the same articulation as a link-to-joint tree. This is often easier to scan than searching only in /Physics when payloads and scopes distribute prims across layers.

  1. Go to Window > Robot Inspector.

  2. Select the Inspire Hand in the robot list.

  3. Set the hierarchy mode to Tree. The default order is parent link, joint, then child link.

  4. Optionally switch to Flat to list all links and joints, or to MuJoCo to view a base-rooted body tree.

  5. Locate the index-finger chain and confirm that it matches the joint visualization.

Robot Inspector displaying the Inspire Hand in Tree mode.

Note

The Deactivate, Bypass, and Anchor columns author transient opinions in a session sublayer. They are useful for debugging but are not saved to your USD files.

When joint visualization is enabled, Robot Inspector displays parent-to-child connection lines in the viewport. It hides the lines during simulation playback.

Enable collider visualization#

The visible meshes are not necessarily the shapes used for contact. Collider visualization shows collision meshes in green for rigid bodies and magenta for static bodies.

  1. Go to Eye > Show by Type > Physics > Colliders > All.

Collider visualization with rigid and static bodies color-coded.

  1. Inspect the wireframes, then select Eye > Show by Type > Physics > Colliders > None to turn them off.

Collider type affects both performance and fidelity. A dexterous hand can use Convex Hull for parts that do not need high accuracy, such as the palm, and Convex Decomposition for detailed contact surfaces, such as fingertips. This tutorial uses Convex Hull for all parts.

Summary#

This tutorial covered:

  • Enabling the joint visualizer and identifying Fixed, Revolute, and Mimic joints.

  • Using Robot Inspector to review the hand’s Flat, Tree, and MuJoCo hierarchy views.

  • Visualizing collision meshes and confirming the Convex Hull collider strategy.

Next Steps#

Continue to Tutorial 3: Collider pairs to identify overlapping self-collision pairs with the Robot Self-Collision Detector.

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