Imported from nvidia/skills (
skills/physical-ai-neural-reconstruction/SKILL.md) via skills.sh. Install upstream withnpx skills add nvidia/skills --skill physical-ai-neural-reconstruction. Copyright stays with the author (Apache-2.0).
Physical AI Neural Reconstruction (NuRec) Router
Purpose
This is a thin router for NVIDIA Neural Reconstruction (NuRec)
requests. It points at the upstream nurec-index skill at
https://github.com/NVIDIA/nurec-skills and its five sibling skills
(physical-ai-datasets, ncore, nre, asset-harvester,
nurec-fixer). Use this skill to:
- Identify which upstream sibling skill answers a NuRec question.
- Locate, clone, or refresh the canonical
nurec-skillscheckout. - Order multi-step NuRec workflows (data → conversion → train → render → cleanup) before opening the upstream recipe.
The canonical recipes (training, rendering, data conversion, dataset downloads, object harvesting, frame cleanup) live in the upstream sibling skills. Never copy or reconstruct their commands here.
Do NOT use this skill for:
- SimReady packaging of CAD or source meshes → use
omniverse-cad-to-simready. - Generic USD performance tuning unrelated to NuRec → use
omniverse-usd-performance-tuning. - AKS / OSMO / NIM Operator infrastructure setup → use
physical-ai-infrastructure-setup-and-resilient-scaling.
When to Use
Read this skill first whenever a user mentions any of:
nurec, nurec router, nurec index, neural reconstruction,
neural reconstruction engine, NRE, 3DGUT, 3DGRT, USDZ,
NCore V4, sensorsim, sensor sim, novel view synthesis,
PhysicalAI-Autonomous-Vehicles-NuRec, PhysicalAI-Robotics-NuRec,
PhysicalAI-NuRec-PPISP, Cosmos-Drive-Dreams, asset harvester,
nurec fixer, DiffusionHarmonizer, harmonizer, difix,
difix3d, carline adaptation, serve-grpc, render-grpc,
warm serve-grpc, nre thin client, batch_render_rgb,
nurec teardown, "where do I start with NuRec", "which NuRec skill
should I use for X?".
Decide which upstream sibling skill answers the question, fetch it (see Locate and fetch the upstream skills), then follow that skill's body.
Prerequisites
The router itself has no runtime prerequisites beyond git for
fetching the upstream. Downstream sibling skills require:
- Linux x86_64 — aarch64 is not supported by
nre. - NVIDIA GPU + driver — CUDA 12.8 capability and >= 24 GB VRAM
(48 GB+ recommended). Ampere (A100/A10/A40/RTX A6000), Ada
(L20/L40/L40S), Hopper (H100/H20): R550+ required, R570+
recommended. Blackwell (RTX Pro 6000D): R580+.
asset-harvesterneeds driver >= 570 and ~16 GB VRAM. - Docker >= 23.0.1 + NVIDIA Container Toolkit >= 1.13.5 — for the
nre,nre-tools, andnurec-fixercontainers (nvcr.io/nvidia/nre/nre-ga:latest,nvcr.io/nvidia/nre/nre-tools-ga:latest, and the locally-builtharmonizer-cosmos-envimage layered onnvcr.io/nvidia/pytorch:25.10-py3). - NGC API key — for pulling
nvcr.iocontainers. Resolution order is$NGC_CLI_API_KEYfirst, then$NGC_API_KEY, and only then prompt the user (seenre'sreferences/ngc-and-registry.md). - Hugging Face token (
HF_TOKEN) with the gated licenses accepted in advance on Hugging Face:nvidia/PhysicalAI-*datasets,nvidia/asset-harvester,nvidia/Harmonizer, andnvidia/Cosmos-Predict2-0.6B-Text2Image. - Python 3.10+ with
huggingface_hubinstalled;pip install nvidia-ncoreforncore; conda (Miniconda / Miniforge) plus GCC 10–13 forasset-harvester. - (Optional) CARLA, Isaac Sim 5.1, or AlpaSim for simulator
integration over
serve-grpc.
Prefer each sibling's scripts/validate_setup.py (present in nre,
asset-harvester, and nurec-fixer) over hand-written checks. For
skills without one (ncore, physical-ai-datasets, this router),
verify secrets without echoing values:
hf auth whoami
[ -n "${HF_TOKEN:-}" ] && echo "HF_TOKEN length=${#HF_TOKEN}" || echo "HF_TOKEN unset"
[ -n "${NGC_CLI_API_KEY:-}" ] && echo "NGC_CLI_API_KEY length=${#NGC_CLI_API_KEY}" || echo "NGC_CLI_API_KEY unset"
[ -n "${NGC_API_KEY:-}" ] && echo "NGC_API_KEY length=${#NGC_API_KEY}" || echo "NGC_API_KEY unset"
See references/secrets-handling.md
for the bash anti-patterns to avoid.
What is NuRec?
NuRec (NVIDIA Omniverse Neural Reconstruction) takes camera, LiDAR, radar, or stereo recordings — typically from a self-driving car or a robot — and turns them into a 3D scene you can re-render from any viewpoint. Names that come up a lot:
- NRE — "Neural Reconstruction Engine". NuRec is the product; NRE
is the engine that trains and renders. Both route to the upstream
nreskill. - USDZ — the file format of a trained scene. A zip archive that Omniverse, Isaac Sim, and CARLA can open.
- NCore V4 — the input format NRE consumes. Raw recordings must be converted to NCore V4 before training.
- 3DGUT / 3DGRT — the two 3D Gaussian Splatting flavours used internally by NRE. The default Hydra recipe picks one; most users never set it manually.
A typical NuRec project has three stages:
- Get the input — convert your own recording to NCore V4
(
ncore), or download a pre-converted dataset (physical-ai-datasets). - Train the reconstruction — feed NCore V4 to NRE; out comes a
USDZ (
nre). - Render new views — render images, videos, or LiDAR sweeps from
the USDZ (
nre).
Projects that just want to use an existing NVIDIA-published scene skip step 2.
Pick a skill
Match the user's goal in the left column and open the named upstream skill on the right. Arrows mean "do these in order".
| I want to… | Upstream skill |
|---|---|
| Find or download a NuRec dataset NVIDIA has published | physical-ai-datasets |
| Convert my own camera / LiDAR / radar / depth / stereo recording into NCore V4 | ncore |
| Write a new converter for an unsupported sensor setup (drone, RGB-D, ROS 2 bag, COLMAP, ScanNet++) | ncore |
| Train a 3D reconstruction from an NCore clip | ncore → nre |
| Generate the extra inputs NRE needs (segmentation masks, depth, ego mask, DINOv2, LiDAR-seg visibility) | nre (uses the nre-tools-ga container) |
| Render a USDZ along the original camera positions | nre |
| Render at full resolution / highest quality | nre (see "Quality presets") |
| Render along a shifted trajectory (e.g. car moved 3 m left) | nre |
| Adapt an existing USDZ to an augmented target-vehicle rig (carline adaptation) | nre (export-custom-rig-trajectory → render) → nurec-fixer |
| Render through a server so CARLA / Isaac Sim / AlpaSim / a custom simulator can ask for frames | nre (serve-grpc) |
| Render the same USDZ many times back-to-back from Python with minimal per-call latency | nre (warm serve-grpc + thin Python client / batch_render_rgb) |
| Render LiDAR sweeps (point clouds) from a USDZ | nre (render-grpc --lidar) |
| Skip training and just render a NuRec scene NVIDIA already built | physical-ai-datasets → nre |
| Skip training and use a pre-built indoor robotics scene | physical-ai-datasets → nre (then Isaac Sim 5.1) |
| Extract individual 3D objects (cars, pedestrians) from a driving clip | asset-harvester |
| Add, remove, or replace cars / pedestrians in a NuRec scene | asset-harvester → nre |
| Clean up or harmonize rendered frames (ghosting, floaters, flicker, lighting/shadows) | nurec-fixer, or --enable-difix inside nre for inline rendering |
| Export the scene as a PLY, mesh, depth maps, ego mask, etc. | nre |
| Upgrade an old USDZ so newer NRE versions load it faster | nre (upgrade-artifact) |
| Open a USDZ or PLY in a browser viewer | nre (viewer / ply_viewer) |
| Measure rendering quality (PSNR, SSIM, LPIPS) against ground truth | nre (eval-rendering-metrics) |
| Benchmark different reconstruction methods on the same scenes | physical-ai-datasets (PhysicalAI-NuRec-PPISP) → nre |
| Train on multiple GPUs or on SLURM | nre |
Common workflows
Seven end-to-end workflows are documented in
references/workflows.md, lettered to
match the upstream nurec-index workflow IDs:
- A. Make a NuRec scene from your own recording.
- B. Use a NuRec scene NVIDIA has already trained.
- C. Use NuRec for indoor robot simulation.
- D. Add, remove, or replace 3D objects in a scene.
- E. Clean up rendered frames.
- F. Benchmark reconstruction quality.
- G. Connect NuRec to a simulator.
Open that file when the user's task spans more than one sibling skill.
Sibling skills (upstream)
Refer to a sibling by its name — that is the portable identifier.
The folder column is only where it lives in a local nurec-skills
checkout.
| Name | Upstream folder | What it does |
|---|---|---|
physical-ai-datasets |
skills/physical-ai-datasets/ |
Catalog and download recipes for every NVIDIA Physical AI dataset on Hugging Face (driving, robotics, manipulation, NuRec scenes, benchmarks). |
ncore |
skills/ncore/ |
Converts any sensor recording to NCore V4 (the format NRE needs), upstream release 2026.04. Also covers writing a new converter. |
nre |
skills/nre/ |
The Neural Reconstruction Engine itself (nvcr.io/nvidia/nre/nre-ga, nvcr.io/nvidia/nre/nre-tools-ga, NRE release_26.04). Trains, performs carline adaptation, renders (locally, via warm serve-grpc + thin Python client / batch_render_rgb, or to an external simulator), exports meshes / point clouds / depth, edits actors, evaluates quality. |
asset-harvester |
skills/asset-harvester/ |
Open-source Apache-2.0 pipeline (SparseViewDiT + TokenGS) that extracts individual 3D objects from sparse views in a driving clip and saves them as .ply Gaussian splats with metadata. |
nurec-fixer |
skills/nurec-fixer/ |
Standalone NVIDIA DiffusionHarmonizer workflow — public successor to the older Fixer / Difix3D+ recipes — that cleans rendered frames, harmonizes inserted actors, evaluates PSNR/LPIPS, and optionally fine-tunes the model. |
For naming overlaps (NRE vs Fixer, ncore vs nre, AV-NuRec vs
Cosmos-Drive-Dreams, NuRec vs SimReady) see
references/mix-ups.md.
Locate and fetch the upstream skills
Try the local disk first, in this order — a sibling skill already installed in the runtime is always preferable to a network fetch:
.agents/skills/<name>/SKILL.md(Cursor, Codex, NemoClaw).claude/skills/<name>/SKILL.md(Claude Code).cursor/skills/<name>/SKILL.md(project-scoped)~/.cursor/skills/<name>/SKILL.md(personal skills)- An existing
nurec-skillsclone under the shared upstream root.
Only if none of those exist, ask the user for explicit consent
before cloning. A git clone is a network fetch of an external
repository plus a write to the local filesystem; it can violate
org network policy and carries supply-chain risk. Show the user
what you intend to run and wait for a yes.
Quick recipe (full version, including the pinned-commit layout, in
references/upstream-fetch.md):
UPSTREAM_ROOT="${NUREC_SKILLS_UPSTREAM_ROOT:-${PHYSICAL_AI_SKILL_HUB_UPSTREAM_ROOT:-$HOME/.physical-ai-skill-hub/upstreams}}"
mkdir -p "$UPSTREAM_ROOT"
if [ -d "$UPSTREAM_ROOT/nurec-skills/.git" ]; then
git -C "$UPSTREAM_ROOT/nurec-skills" fetch --tags
git -C "$UPSTREAM_ROOT/nurec-skills" checkout main
git -C "$UPSTREAM_ROOT/nurec-skills" pull --ff-only
else
# Only after the user has agreed. Prefer --branch <tag-or-sha> over HEAD.
git clone --depth 1 https://github.com/NVIDIA/nurec-skills.git \
"$UPSTREAM_ROOT/nurec-skills"
fi
test -f "$UPSTREAM_ROOT/nurec-skills/skills/nurec-index/SKILL.md"
The upstream tree is rooted at skills/<name>/SKILL.md;
.agents/skills is a symlink onto skills/, so either path
resolves. Read the upstream skill before running any mutating
command:
cat "$UPSTREAM_ROOT/nurec-skills/skills/nurec-index/SKILL.md" # upstream router
cat "$UPSTREAM_ROOT/nurec-skills/skills/<folder>/SKILL.md" # sibling
Companion files (references/, scripts/, assets/) live next to
the sibling's SKILL.md, not next to this router.
Hard Rules
- Router only — do not duplicate upstream NuRec recipes here. Read the upstream sibling skill body before running any mutating command.
- Refer to sibling skills by their
name:(e.g.nre), not by repo path. Folder layouts can change; the name is portable. - Never
git clonethe upstream without explicit user consent. Exhaust the local lookup order first, show the exact command, and clone only into a path the user agreed to — never silently into/tmp. Do not scan broad developer workspaces such as~/Codesor reuse unrelated old clones. - Use the GA container channel:
nvcr.io/nvidia/nre/nre-gaandnvcr.io/nvidia/nre/nre-tools-ga. The un-suffixednvcr.io/nvidia/nre/nre/nre-toolsnames are the legacy channel — still valid for cached version pins, but not what a new workflow should pull. - Resolve the NGC key as
${NGC_CLI_API_KEY:-${NGC_API_KEY:-}}and log in withdocker login nvcr.io --username '$oauthtoken' --password-stdin. Never echo a key. physical-ai-datasetscovers gated Hugging Face datasets. Do not bypass dataset license terms; the user must accept thePhysicalAI-*gated licenses on Hugging Face and provide a token before downloading.- Asset Harvester runs before packaging into a USDZ. Do not call
nre'sexport-external-assetson hand-rolled.plyfiles unless the user explicitly asks to skip Asset Harvester. - For artifact cleanup, prefer the built-in
--enable-difixpath innre. Route to the standalonenurec-fixeronly when the user needs the public code/model card, paired evaluation, fine-tuning, or fixes on previously rendered frames. - Do not invent NRE / NCore / DiffusionHarmonizer commands from
memory. Re-read the upstream sibling skill — versions move fast
(NRE
release_26.04and NCore2026.04are the current pins). - This router does not deploy infrastructure. Route AKS / OSMO /
NIM Operator setup to
physical-ai-infrastructure-setup-and-resilient-scaling.
Limitations
- Router only. This skill never executes mutating NuRec commands. All training, rendering, conversion, and harmonization happens in upstream sibling skills.
- Upstream-pinned. Recipes live in
https://github.com/NVIDIA/nurec-skills, which evolves outside this repo. Stale clones can drift; always refresh the upstream before relying on a sibling skill. - Hand-curated catalogue. A newly-added upstream sibling is not
discoverable here until someone edits the tables (see
references/maintenance.md). - Gated content.
nvidia/PhysicalAI-*,nvidia/asset-harvester,nvidia/Harmonizer, andnvidia/Cosmos-Predict2-0.6B-Text2Imagerequire the user to accept license terms on Hugging Face first. The router cannot bypass this. - Heavy footprint. A complete NuRec workflow can leave 150 GB+
on disk. See
references/teardown.md. - NVIDIA-only stack. Requires Linux x86_64 plus an NVIDIA GPU and the NVIDIA Container Toolkit. aarch64 / AMD / Intel / Apple Silicon are not supported.
- No Omniverse / Isaac Sim integration steps. Handing a USDZ to Isaac Sim 5.1 (workflow C) is documented in the Isaac Sim docs, not in the NuRec skill family.
- Not a SimReady pipeline. NuRec produces a renderable USDZ from
a recording; SimReady packaging of CAD or source meshes is a
different pipeline (see
omniverse-cad-to-simready).
Troubleshooting
| Error / symptom | Likely cause | Solution |
|---|---|---|
nurec-skills clone missing or empty |
Upstream not fetched yet | Walk the local lookup order, then ask consent and run the clone block in Locate and fetch the upstream skills |
test -f .../.agents/skills/SKILL.md fails |
Wrong upstream path — the index lives at skills/nurec-index/SKILL.md |
Use skills/nurec-index/SKILL.md (or the .agents/skills/ symlink alias) |
403/401 pulling nvidia/PhysicalAI-* from HF |
Gated license not accepted, or HF_TOKEN unset / wrong scope |
Accept the gated license on Hugging Face, then hf auth login with a token that has read access |
denied: requested access to the resource is denied from nvcr.io/nvidia/nre/* |
Missing or expired NGC key | docker login nvcr.io with $oauthtoken / ${NGC_CLI_API_KEY:-$NGC_API_KEY}; rotate at org.ngc.nvidia.com/setup/api-key if needed |
manifest unknown / not found pulling an NRE image |
Pulling the legacy un-suffixed name or a tag that channel never published | Pull the GA names nvcr.io/nvidia/nre/nre-ga:latest and nvcr.io/nvidia/nre/nre-tools-ga:latest |
--renderer or export-custom-rig-trajectory rejected as unknown |
Cached image is older than 26.04 / 26.03 |
Pull a 26.04+ GA image; --image-format jpeg works on every family, so don't fall back to PNG |
| NRE refuses to load a clip ("not valid NCore V4") | Recording was not converted | Run the ncore skill before invoking nre |
serve-grpc cold-start latency dominates a Python loop |
One-shot Docker invocation per render | Use the nre warm serve-grpc + thin Python client (batch_render_rgb) recipe; the warm fast path needs a 26.04+ image |
Output files are owned by root after a docker run |
-u $(id -u):$(id -g) was missing |
sudo chown -R "$(id -u):$(id -g)" <output_dir>; add the -u flag next time |
| Frames have ghosting / floaters / flicker after rendering | Inline cleanup not enabled | Re-render with nre --enable-difix, or post-process with nurec-fixer (DiffusionHarmonizer) |
Stale names (ncore-data-conversion, nvidia/Fixer, nvidia/DiffusionHarmonizer weights) in agent output |
Out-of-date cached skill | Update to ncore and nurec-fixer; the model now lives at nvidia/Harmonizer — see references/maintenance.md |
Bash anti-pattern ${HF_TOKEN:+yes}${HF_TOKEN:-no} echoed token value |
Misuse of bash parameter expansion | Rotate the token; use hf auth whoami or length-only checks (see references/secrets-handling.md) |
Cross-skill teardown
A complete NuRec workflow can leave 150 GB+ on disk between
container images, model weights, code clones, conda envs, and output
directories. Each sibling skill has its own dedicated Teardown
section — read them in the order documented in
references/teardown.md when the user no
longer needs the workflow. Do not revoke NGC_API_KEY /
HF_TOKEN as part of teardown unless they were leaked.
Keeping this router up to date
Procedure for adding new sibling skills, renames, or upstream URL
changes lives in references/maintenance.md.
Treat the upstream nurec-index at
https://github.com/NVIDIA/nurec-skills/blob/main/skills/nurec-index/SKILL.md
as authoritative; this skill mirrors only the picker tables, the
workflow ordering, and the upstream fetch recipe.