isaac-sim

name	isaac-sim
description	Use for NVIDIA Isaac Sim simulations — USD scene setup, PhysX stepping, robot articulation, and Replicator synthetic-data generation (SDG). Scripts run one-shot via isaacsim pip wheel in an isolated Python 3.10 venv. Every script must bootstrap `SimulationApp({...})` before any `omni.*` or `isaacsim.*` imports.

isaac-sim

You are connected to NVIDIA Isaac Sim via sim-cli.

Isaac Sim is NVIDIA Omniverse-Kit's embodied-AI simulator (USD + PhysX + RTX). It is sim's solver of choice for synthetic-data generation (Replicator) and robot learning scenes.

Scripts are plain Python. Every script MUST start by constructing SimulationApp(...) before any omni.* / isaacsim.* imports. Execution is one-shot via sim run script.py --solver isaac (v1; v2 will add session).

---

Identity

Field	Value
Solver	NVIDIA Isaac Sim
Execution mode	One-shot subprocess (<venv>/python.exe script.py)
Session type	None (v1)
SDK	isaacsim pip wheel (NVIDIA pypi)
Script language	Python 3.10
Input	.py scripts
Output	JSON on stdout (last line), PNG/USD files, annotations

---

Install

Isaac Sim ships as a large (~15 GB) pip wheel that must live in its own Python 3.10 venv (separate from sim's main Python).

uv venv "<path/to/isaac-venv>" --python 3.10
uv pip install --python "<path/to/isaac-venv>/Scripts/python.exe" \
    "isaacsim[all]" --extra-index-url https://pypi.nvidia.com \
    --index-strategy unsafe-best-match

# Windows persistent:
setx ISAAC_VENV "<path/to/isaac-venv>"
# Unix:
export ISAAC_VENV="<path/to/isaac-venv>"

Verify with sim check isaac — expected status: ok, version: 4.5.

---

Hard constraints

1. SimulationApp first. Every script must:

   from isaacsim import SimulationApp
   simulation_app = SimulationApp({"headless": True})
   # only AFTER this line may you import omni.* or isaacsim.* beyond the app
   

   Linter errors if SimulationApp() is missing; warns if import order is wrong.

2. One process per script. SimulationApp cannot be instantiated twice. Use subprocess boundaries for multi-scene work.

3. Close before exit. simulation_app.close() at end, else process hangs.

4. Replicator needs rep.orchestrator.run(). Defining the graph is not enough — you must trigger execution.

5. OMNI_KIT_ACCEPT_EULA=YES is injected by sim automatically — no user action.

6. JSON on last stdout line. All snippets must print(json.dumps({...})) as the final output for driver.parse_output() to extract.

7. Python 3.10 only. Wheel will refuse to import on 3.11/3.12.

---

File index

base/ — always relevant

Path	Content
base/reference/simulation_app.md	Startup flags, headless, renderer, EULA
base/reference/usd_basics.md	Stage/Prim/Xform, World, DynamicCuboid, step loop
base/reference/replicator.md	omni.replicator.core: distributions, triggers, writers
base/reference/robots.md	Franka, ArticulationView, joint read/write
base/snippets/01_hello_world.py	L1 — drop cube, report ΔZ
base/snippets/02_franka.py	L2 — load Franka, read joints
base/snippets/03_replicator_cubes.py	L3 — SDG, 20 frames + bbox
base/snippets/04_warehouse_sdg.py	L4 — warehouse scene SDG
base/known_issues.md	Failure modes discovered during E2E

sdk/ — version-specific

Path	Content
sdk/4_5/notes.md	Isaac Sim 4.5 API, namespace migration notes

solver/ — solver-version notes

Path	Content
solver/4_5/notes.md	4.5 renderer / Replicator quirks

---

Required protocol

Step 0 — Version check

sim check isaac

Step 1 — Input validation

Input	Category	Action
Script path	A	Must be provided
Output directory	A	Must ask (ISAAC_OUT env or CLI arg)
Frame count / dataset size	A	Must ask
Renderer (RayTracedLighting / PathTracing)	B	Default RayTracedLighting, disclose
Image resolution	B	Default 640×480, disclose

Step 2 — Bootstrap

from isaacsim import SimulationApp
simulation_app = SimulationApp({"headless": True})

Step 3 — Build scene / pipeline

Step 4 — Step or run Replicator

Step 5 — simulation_app.close() + print(json.dumps({...}))

Step 6 — Acceptance validation

Check parsed JSON against user-specified criteria. exit_code == 0 alone is not sufficient.