Source code for isaaclab_newton.sim.spawners.materials.physics_materials_cfg
# Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
# All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
from __future__ import annotations
from collections.abc import Callable
from typing import ClassVar
from isaaclab.sim.spawners.materials.physics_materials_cfg import (
DeformableBodyMaterialBaseCfg,
RigidBodyMaterialFragment,
SurfaceDeformableBodyMaterialBaseCfg,
)
from isaaclab.utils.configclass import configclass
[docs]
@configclass
class NewtonDeformableBodyMaterialCfg(DeformableBodyMaterialBaseCfg, NewtonDeformableMaterialCfg):
"""Newton-specific physics material parameters for volume deformable bodies."""
_usd_namespace: ClassVar[str | None] = "newton"
_usd_applied_schema: ClassVar[str | None] = None
_usd_field_exceptions: ClassVar[dict] = {}
func: Callable | str = "isaaclab.sim.spawners.materials.physics_materials:spawn_deformable_body_material"
k_mu: float = 1e5
"""First Lame material parameter [Pa]. Defaults to 1e5 Pa."""
k_lambda: float = 1e5
"""Second Lame material parameter [Pa]. Defaults to 1e5 Pa."""
k_damp: float = 0.0
"""Damping stiffness for tetrahedral elements [Pa*s]. Defaults to 0.0."""
[docs]
@configclass
class NewtonSurfaceDeformableBodyMaterialCfg(SurfaceDeformableBodyMaterialBaseCfg, NewtonDeformableMaterialCfg):
"""Newton-specific physics material parameters for surface deformable bodies."""
_usd_namespace: ClassVar[str | None] = "newton"
_usd_applied_schema: ClassVar[str | None] = None
_usd_field_exceptions: ClassVar[dict] = {}
func: Callable | str = "isaaclab.sim.spawners.materials.physics_materials:spawn_deformable_body_material"
tri_ke: float = 1e4
"""Triangle area-preserving stiffness [Pa]. Used by Newton backend for cloth meshes."""
tri_ka: float = 1e4
"""Triangle area stiffness [Pa]. Used by Newton backend for cloth meshes."""
tri_kd: float = 1.5e-6
"""Triangle area damping [Pa*s]. Used by Newton backend for cloth meshes."""
edge_ke: float = 5.0
"""Bending stiffness [N*m]. Used by Newton backend for cloth meshes."""
edge_kd: float = 1e-2
"""Bending damping [N*m*s]. Used by Newton backend for cloth meshes."""
[docs]
@configclass
class NewtonMaterialCfg(RigidBodyMaterialFragment):
"""``newton:*`` rigid-body material attributes read by Newton's USD material schema resolver.
Single-namespace fragment (see
:class:`~isaaclab.sim.spawners.materials.RigidBodyMaterialFragment`) for the Newton-only
friction knobs (torsional and rolling friction) and the per-material contact model (contact
stiffness/damping, friction gain, adhesion) that replaces the deprecated per-shape
``ke``/``kd``/``kf``/``ka`` parameters. The ``NewtonMaterialAPI`` schema is applied (and the
``newton:*`` attributes authored) by the generic :func:`~isaaclab.sim.schemas.apply_namespaced`
writer. ``None`` fields are left unchanged.
.. note::
The generated ``NewtonMaterialAPI`` USD schema currently only declares the two friction
attributes; the four contact attributes are still authored as raw ``newton:*`` USD
attributes and are read directly by Newton's schema resolver.
Composes with other rigid-body material fragments (e.g.
:class:`~isaaclab.sim.spawners.materials.UsdPhysicsRigidBodyMaterialCfg`) in the same fragment
list passed to
:func:`~isaaclab.sim.spawners.materials.spawn_rigid_body_material_from_fragments`. For the
legacy (non-fragment) equivalent, see
:class:`~isaaclab_newton.sim.schemas.NewtonMaterialPropertiesCfg`.
"""
_usd_namespace: ClassVar[str | None] = "newton"
_usd_applied_schema: ClassVar[str | None] = "NewtonMaterialAPI"
torsional_friction: float | None = None
"""Torsional friction coefficient (resistance to spinning at a contact point) [dimensionless].
Writes ``newton:torsionalFriction``. Range: [0, inf).
"""
rolling_friction: float | None = None
"""Rolling friction coefficient (resistance to rolling motion) [dimensionless].
Writes ``newton:rollingFriction``. Range: [0, inf).
"""
contact_stiffness: float | None = None
"""Contact normal-force stiffness [N/m].
Writes ``newton:contactStiffness``. Replaces the deprecated per-shape ``ke`` contact parameter;
used by the SemiImplicit, Featherstone, MuJoCo, and VBD solvers.
"""
contact_damping: float | None = None
"""Contact normal-force damping coefficient [N·s/m].
Writes ``newton:contactDamping``. Replaces the deprecated per-shape ``kd`` contact parameter;
used by the SemiImplicit, Featherstone, MuJoCo, and VBD solvers.
"""
contact_friction_gain: float | None = None
"""Friction-force stiffness gain used by the tangential (friction) contact response [N·s/m].
Writes ``newton:contactFrictionGain``. Replaces the deprecated per-shape ``kf`` contact
parameter; used by the SemiImplicit and Featherstone solvers.
"""
contact_adhesion: float | None = None
"""Contact adhesion distance: shapes closer than this threshold experience an attractive
(adhesive) force [m].
Writes ``newton:contactAdhesion``. Replaces the deprecated per-shape ``ka`` contact parameter;
used by the SemiImplicit and Featherstone solvers.
"""
