hcislab/digital-twin

Intelligent Home Care Living Lab — Digital Twin

A USD digital twin of the Intelligent Home Care Living Lab (alias: NYCU Room 305), built by the Human-centered Intelligent System Lab (hcislab) — GitHub @HCIS-Lab. Authored for NVIDIA Isaac Sim 5.1.

This is a foundation twin: it is the room only — no furniture, no robot, no task props. Every project references it and layers its own content on top (a robot, furniture, graspables, sensors) without editing the twin. That keeps one canonical, physics-ready room shared across projects.

Lab links: GitHub @HCIS-Lab · HF @hcislab

What's new (2026-07-04)

• Physical properties are now set. Every room surface is a static collider (exact triangle-mesh, physics:approximation = "none") and the scene carries a PhysicsScene + a ground physics material (friction, no bounce). Robots and props now rest on / collide with the room instead of falling through.
• Structured into layers. The monolithic file is split into a visual layer, a collider layer, and a thin top composition — so you can reference exactly what you need (visual only, or visual + physics).

Contents

room.usd                   # ← ENTRY POINT. Top composition: Z-up / meters / kg,
                           #   references the visual layer + sublayers the collider layer,
                           #   adds a PhysicsScene and the ceiling RectLight.
nycu_lights.usdz           # VISUAL layer — geometry (443 meshes, ~188k pts) + 417 materials
                           #   + bundled textures + DomeLight. No physics. Self-contained.
room_collider.usd          # COLLIDER layer — an overlay that adds CollisionAPI (approx=none)
                           #   to every room mesh + a ground physics material bound at /Room.
nycu_light_collider.usd    # COMPAT SHIM — the historic entry point; now just references
                           #   room.usd</Room>. Kept so existing pipelines don't break.

room.usd references nycu_lights.usdz and sub-layers room_collider.usd by relative paths, so all files must stay side by side. snapshot_download keeps them together automatically.

Scene stats (Isaac Sim 5.1): 443 meshes (~188k points), 417 materials, a DomeLight + RectLight, 443 static mesh colliders. Approx extent 12.1 × 7.0 × 3.4 m.

Usage

from huggingface_hub import snapshot_download

path = snapshot_download(repo_id="hcislab/digital-twin", repo_type="dataset")
# open path/room.usd in Isaac Sim 5.1  (or the legacy nycu_light_collider.usd — same content)

In Isaac Sim (Python):

import omni.usd
omni.usd.get_context().open_stage(f"{path}/room.usd")

Build your project on top (don't edit the twin)

Reference the foundation onto your own prim and add your layers beside it:

from pxr import Usd, UsdGeom
stage = Usd.Stage.CreateNew("my_project_scene.usd")
UsdGeom.SetStageUpAxis(stage, UsdGeom.Tokens.z)
UsdGeom.SetStageMetersPerUnit(stage, 1.0)
room = UsdGeom.Xform.Define(stage, "/World/Room")
room.GetPrim().GetReferences().AddReference(f"{path}/room.usd")   # foundation, untouched
# ... now add /World/Robot, /World/Furniture, /World/Props as your own prims ...

Reference nycu_lights.usdz instead if you want the room's visuals without physics.

Physics notes

• Colliders are static (no RigidBodyAPI on the room) with physics:approximation = "none" — the exact triangle mesh is used for collision. Correct and cheap for an immovable environment.
• Ground physics material /Room/PhysicsMaterials/Ground: staticFriction 0.9, dynamicFriction 0.8, restitution 0. Generic and project-neutral — bound at /Room (inherits to all room colliders).
• PhysicsScene gravity = −Z, 9.81 m/s².

Notes

• Textures are bundled inside nycu_lights.usdz and resolve via relative paths — verified self-contained with UsdUtils.ComputeAllDependencies (no unresolved dependencies).
• Two references resolve at runtime in Isaac Sim / Omniverse and are intentionally not bundled:
  • OmniGlass.mdl — Omniverse stock material library.
  • A Cloudy dome-light HDR served from the Omniverse content CDN. Materials and dome lighting need an Omniverse asset connection / cache to display fully; geometry, the RectLight, and all physics load without it.
• Verified to open cleanly in Isaac Sim 5.1 from a fresh download, and to load (443 meshes + colliders) when referenced by a downstream scene.

Citation

If you use this digital twin, please cite it:

@misc{hcislab_ihcll_2026,
  title        = {Intelligent Home Care Living Lab Digital Twin},
  author       = {{Human-centered Intelligent System Lab}},
  year         = {2026},
  howpublished = {Hugging Face dataset},
  url          = {https://huggingface.co/datasets/hcislab/digital-twin},
  note         = {NVIDIA Isaac Sim 5.1 USD digital twin; alias NYCU Room 305}
}

A machine-readable CITATION.cff is included (Hugging Face renders a "Cite this" entry from it).

License

CC BY-NC 4.0 (Creative Commons Attribution-NonCommercial 4.0).

• ✅ Share and adapt for non-commercial research/education, with attribution (cite as above).
• ❌ No commercial use without separate permission from the lab. For commercial licensing, contact hcislab01@gmail.com.

Note: the referenced OmniGlass.mdl and dome-light HDR are NVIDIA Omniverse assets governed by their own licenses; they are not redistributed here.