> ## Documentation Index
> Fetch the complete documentation index at: https://docs.godrift.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Isaac Sim
> Compose, launch, and verify NVIDIA Isaac Sim scenes from prompts — on RTX hardware
Drift drives NVIDIA Isaac Sim the same way it drives Gazebo and MuJoCo: describe the scene, Drift writes it, boots Isaac Sim, and checks the result. Isaac Sim is the right target when you need RTX-quality rendering, USD assets, or an Omniverse pipeline.
Isaac Sim is GPU-bound in a way Gazebo and MuJoCo are not. Read the requirements below before you start — Drift checks them for you and tells you plainly when a machine can't hold an Isaac Sim window open.
## Requirements
| Requirement | Needed for |
| ---------------------------------------------------------------------------- | ------------------------------- |
| NVIDIA GPU with RT cores (GeForce RTX, RTX A-series, RTX PRO) | Any Isaac Sim rendering |
| 16 GB of GPU memory or more | An interactive Isaac Sim window |
| Isaac Sim 5.1 or 6.0 — the pip package or the standalone binary distribution | Launching and verifying scenes |
Datacenter compute cards without RT cores (A100, H100, …) can't run Isaac's RTX renderer. Virtual machines and containers without GPU passthrough won't work either.
What Drift can do depends on what it finds on your machine:
| Your machine | What works |
| ---------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- |
| RTX GPU with 16 GB+, Isaac Sim installed | Everything — compose, launch interactively, verify with a rendered video |
| RTX GPU under 16 GB, Isaac Sim installed | Compose and verify headlessly. Drift won't open an interactive window (it can freeze the machine); it renders to video instead, and asks first — see below |
| RTX GPU, Isaac Sim not installed | Compose and validate the scene on disk. Ask Drift to help you install Isaac Sim |
| No RTX GPU | Compose and validate the scene on disk only. Drift won't offer to install Isaac Sim, because it couldn't render here |
Don't have Isaac Sim yet? Ask:
```drift theme={null}
install missing packages for Isaac Sim
```
Drift walks you through NVIDIA's install steps. It never starts the multi-gigabyte install on its own.
## Composing a scene
```drift theme={null}
compose a warehouse floor in Isaac Sim with three pallet racks and a conveyor
along the north wall, and import my robot from ./robots/arm.urdf with a fixed
base on the workbench
```
Drift writes a declarative scene spec next to your other project files, named `.isaac.json`. The spec is checked before Isaac Sim ever boots — a bad spec is rejected up front and never overwrites a good one. Drift also accepts specs written in Isaac's own vocabulary, so you can hand-edit the file and ask Drift to reload it.
## Launching and verifying
```drift theme={null}
launch the Isaac scene
```
On a qualifying GPU this opens the interactive Isaac Sim viewer. Drift tracks the process like any other simulator — `/ps` shows it, `/exit` cleans it up.
```drift theme={null}
verify the Isaac scene
```
Verification runs headlessly: Drift steps the physics, records a short video, runs a battery of numeric checks (does anything fall through the floor, fly apart, or drift away?), and looks at the frames to confirm the scene matches what you asked for.
The verdict says *what* failed and *why*. A scene problem is reported as a scene problem; an environment problem (driver, GPU, install) as an environment problem — so you aren't sent chasing the wrong thing.
## The GPU prompt on smaller cards
On an RTX card under 16 GB, a verification render still helps Drift check its own work, but it competes hard for the GPU. So, once per session, Drift asks:
```
⚠️ Isaac rendering is GPU-heavy
This machine's GPU is below Isaac's recommended 16GB, so a render competes
hard for the GPU while it runs. Render here?
Yes - render
Yes, don't ask again
No - skip renders this session
No, don't ask again
```
A "don't ask again" answer is saved for the current workspace in `.drift/settings.json` — remove it there if you change your mind. If you skip the render, Drift reports the scene as *not visually verified yet* rather than pretending it passed.
## Viewing library robots in Isaac Sim
Robots in the [Robot Library](/guides/robot-library) that ship a USD variant offer **View in Isaac Sim** from `/robots`. Pick the robot, choose the **USD** format, then **View in Isaac Sim**. Only robots with a USD variant show the option, and USD robots open on their own — the pre-composed demo worlds are MuJoCo-only.
## Next steps
Browse 100+ robots and open the USD ones straight in Isaac Sim
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