As far as I can tell, this is what you want.

Abstract:

This tutorial, Part 3 of a series, explains how to use Rerun's entity hierarchy and Transform3D archetype to create complex animations. Using a solar system as an example, it demonstrates how to establish parent-child relationships between 3D objects (sun, planet, moons). The core concept is defining an object's position relative to its parent (e.g., a moon relative to its planet) rather than using global coordinates. This approach simplifies the management of multi-body systems, a common requirement in robotics. The video also contrasts log_tick and log_time for controlling animation speed and highlights Rerun's ability to log different components of an entity at different timestamps.

Mastering Rerun's 3D Transforms and Entity Hierarchies

• 0:19 Entity Hierarchies: The video introduces 3D transforms and the entity hierarchy, a core Rerun feature for creating parent-child relationships between logged objects to build complex scenes.
• 0:37 Solar System Example: A simple solar system is built to demonstrate how transforms cascade. The planet's position is defined relative to the sun, and the moons' positions are defined relative to the planet.
• 1:03 Robotics Application: This relative positioning pattern is directly applicable to robotics, such as defining a robot hand's location in relation to its elbow, which is much simpler than managing all positions in a global coordinate system.
• 4:59 The Transform3D Archetype: The rr.Transform3D archetype is the key tool used to apply translations and rotations. The entity path itself (e.g., logging a moon to sun/planet/moon1) establishes the parent-child link for transform inheritance.
• 7:04 Animation Pacing (log_tick vs log_time): The tutorial explains the difference between logging with wall-clock time (log_time) and sequence time (log_tick). log_tick is used to ensure a smooth, evenly-paced animation regardless of how quickly the script executes.
• 8:50 Decoupled Component Logging: A powerful feature of Rerun is highlighted: you can log an entity's static properties (like its geometry and color) at one time, and then log its changing properties (like its position via Transform3D) at many subsequent times.
• 10:09 Foundational Skills: This tutorial covers the fundamental Rerun concepts of archetypes, 3D relationships, and time. Future videos will apply these skills to real-world data.