Add rendering functionals by loliverhennigh · Pull Request #1618 · NVIDIA/physicsnemo

loliverhennigh · 2026-05-05T17:21:03Z

PhysicsNeMo Pull Request

Description

Rendering Kernels

copy-pr-bot · 2026-05-05T17:21:07Z

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greptile-apps · 2026-05-05T17:24:23Z

Greptile Summary

This PR adds a new physicsnemo.nn.functional.rendering package with eight GPU-accelerated rendering primitives (isosurface ray-marching, volume rendering, mesh ray-casting, LIC, point cloud, wireframe, and scalar/vector-field RGBA transfer functions) backed by custom Warp kernels and optional PyTorch fallbacks. The FunctionSpec dispatch pattern and test coverage are solid, but several correctness and portability issues in the core Warp implementation file need attention before merging.

TOCTOU race in wireframe rasterization — _write_depth_tested_pixel uses wp.atomic_min for depth but writes color non-atomically; two threads at similar depths can both pass the depth test and write their colors in an unordered way, producing incorrect results.
wp.init() at module import time — calling Warp initialization unconditionally at the top of _warp_impl.py causes every import of the rendering package to initialize the GPU, breaking CPU-only and Warp-free environments even when only the PyTorch backends are needed.
GPU validation gaps — camera and bounds sanity checks in _camera_basis and _bounds_tensor are skipped on CUDA devices, so degenerate inputs (eye == center, up parallel to view, invalid bounds) silently produce corrupted renders on GPU.

Important Files Changed

Filename	Overview
physicsnemo/nn/functional/rendering/_warp_impl.py	Core Warp kernel file; contains a TOCTOU race in _write_depth_tested_pixel, module-level wp.init() at import time, GPU-only validation gaps in _camera_basis/_bounds_tensor, a hardcoded 8192-step cap for line rasterization, and no near-plane clipping for wireframe edges.
physicsnemo/nn/functional/rendering/_torch_impl.py	Pure-PyTorch fallback implementations for scalar_field_to_rgba and vector_field_to_rgba; logic is clean and correct.
physicsnemo/nn/functional/rendering/isosurface_render.py	FunctionSpec wrapper for isosurface ray-marching; delegates to warp backend, validation and make_inputs_forward look correct.
physicsnemo/nn/functional/rendering/mesh_raycast.py	FunctionSpec wrapper for BVH mesh ray-casting; input validation and dispatch are correct.
physicsnemo/nn/functional/rendering/wireframe_render.py	Thin FunctionSpec wrapper for wireframe rasterization; the underlying kernel issues are in _warp_impl.py.
physicsnemo/nn/functional/rendering/point_cloud_render.py	FunctionSpec wrapper for two-pass point cloud rasterization; uses race-safe atomic key scheme unlike wireframe.
physicsnemo/nn/functional/rendering/volume_render.py	VolumeRender FunctionSpec wrapper; front-to-back compositing logic is correct.
physicsnemo/nn/functional/rendering/scalar_field_to_rgba.py	ScalarFieldToRGBA with warp and torch backends; compare_forward tolerance looks appropriate.
physicsnemo/nn/functional/rendering/vector_field_to_rgba.py	VectorFieldToRGBA with warp and torch backends; logic mirrors scalar_field_to_rgba correctly.
physicsnemo/nn/functional/rendering/line_integral_convolution.py	LineIntegralConvolution FunctionSpec wrapper; delegates to warp kernel, looks correct.
physicsnemo/nn/functional/rendering/init.py	Exports all rendering classes and functional aliases; all is complete and consistent.

_{Reviews (1): Last reviewed commit: "Add rendering functionals" | Re-trigger Greptile}

loliverhennigh · 2026-05-06T18:28:03Z

/blossom-ci

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loliverhennigh · 2026-05-06T18:51:02Z

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loliverhennigh · 2026-05-06T20:40:54Z

/blossom-ci

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loliverhennigh · 2026-05-07T06:06:02Z

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loliverhennigh · 2026-05-07T08:10:03Z

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loliverhennigh · 2026-05-07T22:34:47Z

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loliverhennigh · 2026-05-07T22:45:12Z

/blossom-ci

megnvidia

lgtm

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loliverhennigh · 2026-05-08T18:20:17Z

/blossom-ci

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loliverhennigh · 2026-05-11T19:02:09Z

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loliverhennigh · 2026-06-02T22:01:53Z

/blossom-ci

mehdiataei · 2026-06-04T19:39:04Z

Amazing! LGTM!

mehdiataei · 2026-06-04T20:37:05Z

/ok to test ebabe20

copy-pr-bot · 2026-06-04T20:37:09Z

/ok to test ebabe20

@mehdiataei, there was an error processing your request: E2

See the following link for more information: https://docs.gha-runners.nvidia.com/cpr/e/2/

loliverhennigh · 2026-06-15T14:50:11Z

/blossom-ci

loliverhennigh · 2026-06-15T14:50:12Z

/ok to test e037999

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loliverhennigh · 2026-06-15T19:51:34Z

/blossom-ci

loliverhennigh · 2026-06-15T19:51:34Z

/ok to test 938e8f7

loliverhennigh · 2026-06-15T20:50:15Z

/ok to test 938e8f7

loliverhennigh · 2026-06-15T20:50:15Z

/blossom-ci

loliverhennigh · 2026-06-16T01:19:59Z

/ok to test 938e8f7

loliverhennigh · 2026-06-16T01:19:59Z

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loliverhennigh · 2026-06-16T05:19:00Z

/ok to test 938e8f7

loliverhennigh · 2026-06-16T05:19:00Z

/blossom-ci

loliverhennigh · 2026-06-16T09:40:46Z

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loliverhennigh · 2026-06-16T09:40:47Z

/ok to test 938e8f7

loliverhennigh · 2026-06-16T13:46:50Z

/blossom-ci

loliverhennigh · 2026-06-16T13:46:50Z

/ok to test 938e8f7

loliverhennigh · 2026-06-16T14:55:49Z

/blossom-ci

loliverhennigh · 2026-06-16T14:55:50Z

/ok to test 938e8f7

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loliverhennigh · 2026-06-23T21:48:55Z

/blossom-ci

loliverhennigh · 2026-06-23T21:48:56Z

/ok to test c86ae80

loliverhennigh · 2026-06-24T06:10:58Z

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loliverhennigh · 2026-06-24T06:10:59Z

/ok to test c86ae80

loliverhennigh · 2026-06-24T06:13:12Z

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loliverhennigh · 2026-06-24T06:13:13Z

/ok to test c86ae80

loliverhennigh · 2026-06-24T17:53:25Z

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loliverhennigh · 2026-06-24T17:53:26Z

/ok to test c86ae80

* Add rendering functionals * Move rendering examples under functional examples * Document rendering functional helpers * Align isosurface error test with CUDA validation * Align rendering functionals with functional layout * Move rendering backends into functional packages * Remove rendering Warp import initialization * Address rendering review comments --------- Co-authored-by: Oliver Hennigh <oliverhennigh@Olivers-MacBook-Air.local>

Add rendering functionals

ebabe20

loliverhennigh requested review from ktangsali and megnvidia as code owners May 5, 2026 17:21

greptile-apps Bot reviewed May 5, 2026

View reviewed changes

Move rendering examples under functional examples

df05f9a

loliverhennigh added 2 commits May 6, 2026 11:50

Document rendering functional helpers

5094323

Merge remote-tracking branch 'upstream/main' into feature/rendering-f…

e5fdd97

…unctionals

Merge remote-tracking branch 'upstream/main' into feature/rendering-f…

9733a46

…unctionals

Align isosurface error test with CUDA validation

16ee6af

Align rendering functionals with functional layout

d420dea

Move rendering backends into functional packages

fe6ff58

megnvidia approved these changes May 8, 2026

View reviewed changes

Merge remote-tracking branch 'upstream/main' into feature/rendering-f…

2f9dbec

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Merge remote-tracking branch 'upstream/main' into feature/rendering-f…

7b94ba2

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Merge remote-tracking branch 'upstream/main' into feature/rendering-f…

31f6ed6

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Merge remote-tracking branch 'upstream/main' into feature/rendering-f…

938e8f7

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Merge remote-tracking branch 'upstream/main' into feature/rendering-f…

c86ae80

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loliverhennigh added this pull request to the merge queue Jun 24, 2026

Merged via the queue into NVIDIA:main with commit f8d5d2f Jun 24, 2026
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loliverhennigh commented May 5, 2026

PhysicsNeMo Pull Request

Description

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greptile-apps Bot commented May 5, 2026

Greptile Summary

Important Files Changed

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