Air hockey

Basic contacts

A robot arm strikes a puck into the far goal.

Play0.00 s

¼×½×1×2×

Loop

The steel preset (the default), recordedon an NVIDIA RTX PRO 6000 Blackwell.

Run it

cd examples
# the default preset (steel), then the others
uv run shelf play air_hockey
# change solver settings live
uv run shelf tune air_hockey

Source: examples/shelf/01_basic_contacts/air_hockey/ · ported from steel-webgpu assets/scenes/air_hockey (hero_montage export) @ ad03e49

Presets

Preset	Solver	Status	Checked
steeldefault	steel	works	2026-11-10, newton f6fc82a8b, NVIDIA RTX PRO 6000 Blackwell Server Edition

Solvers with no row are untested on this example. The full settings are inpresets.toml.

Code

example.py

examples/shelf/01_basic_contacts/air_hockey/example.py

# SPDX-FileCopyrightText: Copyright (c) 2026 Skild AI and the Steel contributors
# SPDX-License-Identifier: Apache-2.0
# Direct source: steel-webgpu; see presets.toml and THIRD_PARTY.md.
# Modified for Steel Shelf: preset-driven execution and shared runner integration.

###########################################################################
# Example Air hockey
#
# A robot arm with a mallet strikes a free puck across the table and into the far goal.
#
# Rebuilt from steel-webgpu's exported scene (assets/scenes/air_hockey: scene.json
# and scene.bin, copied next to this file); see common/exported_scene.py. The
# visual meshes draw when a steel-webgpu checkout sits next to the shelf.
#
# Command: python -m shelf run air_hockey
#
###########################################################################

import newton.examples
from common.exported_scene import ExportedSceneExample


class Example(ExportedSceneExample):
    file = __file__


if __name__ == "__main__":
    parser = Example.create_parser()
    viewer, args = newton.examples.init(parser)
    newton.examples.run(Example(viewer, args), args)

example.py on GitHub

presets.toml

examples/shelf/01_basic_contacts/air_hockey/presets.toml

example = "air_hockey"
source = "steel-webgpu assets/scenes/air_hockey (hero_montage export) @ ad03e49"
default = "steel"

[check]
# Arguments `python -m shelf check` passes in test mode.
args = []

[gallery]
short = "A robot arm strikes a puck into the far goal."
title = "Air hockey"
frame = 420

[xpbd]
status = "untested"

[vbd]
status = "untested"

[mujoco]
status = "untested"

[featherstone]
status = "untested"

[semi_implicit]
status = "untested"

[feather_pgs]
status = "untested"

[steel]
status = "works"
# 3 substeps x 10 iterations (1.95 ms/frame on an RTX PRO 6000, the port's 4 x 16 4.29): the mallet strikes the puck
# at frame 139 (2.2 m/s) and it is in the far goal by frame 168 and stays there, as in a 16 x 48 run; penetration
# peak 1.0-1.6 mm as the puck hits the goal, mean 0.05-0.08 mm. 3 x 8 gives 1.4 mm, 2 substeps 7-8 mm; 4 x 8 (2.39 ms)
# keeps it to 0.07 mm.
# The arm's limits (+-2 pi) are never reached and the joints' velocity limits are 1e6 (none), so both row kinds are
# off; the row capacities fit the scene (peak 26 propagation rows, 15 contacts) instead of the port's 8192/1024/16384.
sim = { fps = 60, substeps = 3 }
solver = { solve_mode = "matrix_free", iterations = 10, articulated_contact_response = "propagation_colored", enable_joint_velocity_limits = false, enable_joint_limits = false, enable_sleeping = true, free_body_constraint_max = 64, articulation_constraint_max = 64, propagation_constraint_max = 128 }
checked = "2026-11-10, newton f6fc82a8b, NVIDIA RTX PRO 6000 Blackwell Server Edition"

[kamino]
status = "untested"

[implicit_mpm]
status = "untested"

[style3d]
status = "untested"

presets.toml on GitHub

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