novaphy.ModelBuilder¶

Mutable scene-construction API. Add bodies, shapes, joints, articulations, fluid blocks, and imported assets, then call finalize() to produce an immutable Model.

import novaphy
import numpy as np

builder = novaphy.ModelBuilder()
builder.add_ground_plane(y=0.0)

body = novaphy.RigidBody.from_box(1.0, np.array([0.5, 0.5, 0.5], dtype=np.float32))
idx = builder.add_body(body, novaphy.Transform.from_translation(np.array([0, 5, 0])))
builder.add_shape(novaphy.CollisionShape.make_box(np.array([0.5, 0.5, 0.5]), idx))

model = builder.finalize()

Body and Shape¶

Method	Purpose
`add_body(body, transform=Transform.identity()) -> int`	Add a rigid body. Returns body index.
`add_link(...) -> int`	Newton-aligned link/body creation helper for articulated systems.
`add_ground_plane(y=0.0, friction=0.5, restitution=0.0) -> int`	Add an infinite ground plane shape. Returns shape index.
`add_shape(shape) -> int`	Add a `CollisionShape`. Returns shape index.
`add_shape_box(...)`	Newton-style deferred shape creation.
`add_shape_sphere(...)`	Newton-style deferred shape creation.
`add_shape_plane(...)`	Add a plane shape.
`add_shape_cylinder(...)`	Newton-style deferred cylinder shape creation.
`add_shape_convex_hull(...)`	Add a convex hull from a `Mesh` or vertex list.
`add_shape_convex_hull_with_inertia(...)`	Add a convex hull using precomputed inertia data.
`add_shape_mesh(mesh=..., ...)`	Add a triangle-mesh shape (uses `Mesh` precomputed inertia when present).
`add_shape_mesh_with_inertia(...)`	Add a triangle mesh using precomputed inertia data.
`add_shape_to_body(body_index, shape)`	Attach an existing `CollisionShape` to a body.
`add_shape_collision_filter_pair(shape_a, shape_b)`	Disable collision for a pair of finalized/eager shape indices.

Particles¶

Method	Purpose
`add_particle(pos, vel, mass, radius=None)`	Add one particle.
`add_particles(pos, vel, mass, radius=None)`	Add a batch of particles.

Joints and Articulations¶

Method	Purpose
`add_joint(joint_type, parent, child, ...)`	Generic Newton-style joint factory.
`add_joint_revolute(parent, child, axis: JointDofConfig, ...)`	Add a revolute joint between two body indices.
`add_joint_prismatic(...)`	Add a 1-DOF translational joint.
`add_joint_ball(...)`	Add a 3-DOF spherical joint.
`add_joint_fixed(...)`	Add a 0-DOF rigid attachment.
`add_joint_free(...)`	Add a 6-DOF floating-base joint.
`add_joint_distance(...)`	Add a scalar distance constraint.
`add_joint_d6(...)`	Add a configurable 0-6 DOF joint from axis configs.
`add_joint_cable(...)`	Add a scalar cable / rope constraint.
`add_articulation(joints, label="") -> int`	Group joint indices into an articulation. Returns articulation index.

Multiworld and Metadata¶

Method	Purpose
`begin_world(label=None, attributes=None, gravity=None)` / `end_world()`	Add subsequent bodies, joints, shapes, and particles to one world slice. Passing per-world gravity by keyword is clearest.
`add_world(builder, xform, ...)`	Append another builder as a world instance and record `xform.position` as that world's physical origin.
`replicate(builder, num_worlds, spacing)`	Replicate a builder into multiple world slices, spaced by `spacing`, and expose those origins through `Model.world_origins`. The legacy keyword `world_count` remains accepted as a compatibility alias for `num_worlds`.
`set_gravity(gravity)`	Set default builder gravity.
`add_site(...)` / `add_site_on_link(...)`	Add named attachment points for sensors and importers.
`request_state_attributes(...)`	Request optional state-side storage.
`request_contact_attributes(...)`	Request optional contact-side storage such as `force`.
`set_broad_phase_mode(mode)`	Select default broadphase mode for finalized collision pipelines.

Asset Import¶

Method	Purpose
`add_urdf(source, **kwargs)`	Parse a URDF file/path or XML source through the public builder wrapper.
`add_mjcf(source, *, ...)`	Parse a MuJoCo XML file/path or XML source. Its import controls are keyword-only. Returns articulation index (or `-1` if empty).
`add_mjcf_string(xml_text, options=None)`	Parse an in-memory MJCF XML string.
`add_usd(source, *, ...)`	Parse a text PhysX USD articulation from a file, including bodies, supported joints, and collision shapes. Returns its root body index.

MJCF coverage includes nested bodies, box / sphere / capsule / cylinder / plane geoms, hinge / slide / ball / free joints, inertial blocks, and world-level gravity. URDF is available both through add_urdf and the dedicated I/O pipeline. add_usd is a separate, text-based PhysX articulation path; the smaller USDA snapshot pipeline uses the dedicated importer—see novaphy.io.

Finalize¶

Method	Purpose
`finalize(device=Device.cpu(), requires_grad=False) -> Model`	Bake into an immutable `Model`. Newton-aligned signature.

Properties¶

Property	Description
`num_bodies`	Number of currently added bodies.
`num_shapes`	Number of currently added shapes.
`num_sites`	Number of currently added sites.
`current_world`	Index of the currently open world slice, or `-1` for the global/no-open-world sentinel.
`broad_phase`	Builder default broadphase mode.
`default_shape_cfg`	Default shape configuration used by helper methods.
`default_particle_radius`	Default particle radius for particle helpers.