Core

This section documents the core data structures and simulation objects in Newton Physics.

Classes

newton.Model([device])	Holds the definition of the simulation model
newton.State()	Time-varying state data for a Model.
newton.Control()	Time-varying control data for a Model.
newton.ModelBuilder([up_axis, gravity])	A helper class for building simulation models at runtime.
newton.Mesh(vertices, indices[, ...])	Describes a triangle collision mesh for simulation
newton.SDF([volume, I, mass, com])	Describes a signed distance field for simulation

class newton.Axis(value)

Enum for representing the three axes in 3D space.

X = 0

Y = 1

Z = 2

newton.AxisType

alias of Axis | Literal[‘X’, ‘Y’, ‘Z’] | Literal[0, 1, 2] | int | str

Geometry Types

These constants define the supported geometry types for rigid body shapes in Newton simulations. They are defined in newton.core.types and are used when assigning collision geometry to bodies or shapes.

Constant	Description
GEO_SPHERE	A sphere defined by a center and radius.
GEO_BOX	An axis-aligned box defined by half-extents.
GEO_CAPSULE	A capsule defined by two endpoints and a radius.
GEO_CYLINDER	A cylinder defined by two endpoints and a radius.
GEO_CONE	A cone aligned along an axis with a base radius and height.
GEO_MESH	A triangle mesh with vertex and face data.
GEO_SDF	A signed distance field represented on a grid.
GEO_PLANE	An infinite plane defined by a normal and offset.
GEO_NONE	No geometry; used to mark inactive or undefined shapes.

Joint Types

These constants define the supported types of joints used to constrain motion between rigid bodies. They are defined in newton.core.types and used when constructing models.

Constant	Description
JOINT_PRISMATIC	Allows translation along a single axis (prismatic joint).
JOINT_REVOLUTE	Allows rotation around a single axis (revolute/hinge joint).
JOINT_BALL	Allows rotation in all directions around a point (ball joint).
JOINT_FIXED	Prevents all relative motion (fixed joint).
JOINT_FREE	Allows full freedom (no constraints between bodies).
JOINT_COMPOUND	A compound joint made from multiple constraints.
JOINT_UNIVERSAL	Allows two rotational degrees of freedom (universal joint).
JOINT_DISTANCE	Constrains two points to a fixed distance (distance joint).
JOINT_D6	6-DoF joint with configurable limits per axis.

Particle Flags

These flags indicate special states or behaviors for particles in Newton simulations. They are defined in newton.core.types and can be used to tag or filter particles.

Constant	Description
PARTICLE_FLAG_ACTIVE	The particle is active and should be simulated.

Shape Flags

These flags control rendering and collision behavior for shapes in Newton simulations. They are defined in newton.core.types and can be bitwise ORd together to configure shape behavior.

Constant	Description
SHAPE_FLAG_VISIBLE	Shape is visible in rendering.
SHAPE_FLAG_COLLIDE_SHAPES	Enables collision with other shapes.
SHAPE_FLAG_COLLIDE_GROUND	Enables collision with ground planes or static terrain.

Update Flags

These bitmask flags are used with newton.solvers.SolverBase.notify_model_changed() to inform a solver which parts of a newton.Model were modified after the solver was created. Individual solver implementations are responsible for interpreting these flags and updating any internal data structures from the model as required.

Constant	Description
NOTIFY_FLAG_JOINT_PROPERTIES	Joint transforms or coordinates have changed.
NOTIFY_FLAG_JOINT_AXIS_PROPERTIES	Joint axis limits, targets, or modes have changed.
NOTIFY_FLAG_DOF_PROPERTIES	Joint DOF state or force buffers have changed.
NOTIFY_FLAG_BODY_PROPERTIES	Rigid-body pose or velocity buffers have changed.
NOTIFY_FLAG_BODY_INERTIAL_PROPERTIES	Rigid-body mass or inertia tensors have changed.
NOTIFY_FLAG_SHAPE_PROPERTIES	Shape transforms or geometry have changed.