novaphy.solvers.VBDConfig¶

Configuration object consumed by novaphy.solvers.SolverVBD. It is also available as novaphy.solvers.SolverVBD.Config.

The time step is not stored here: pass dt to solver.step(state_in, state_out, control, contacts, dt). Gravity belongs to the Model, not this configuration object.

Core attributes¶

Attribute	Description
`iterations`	VBD / AVBD solve iterations per call to `step()`.
`friction_epsilon`	Regularization used by friction constraints.
`integrate_with_external_rigid_solver`	Preserve externally integrated rigid-body state while VBD advances particles.
`backend`	VbdBackend: `CPU`, `CUDA`, or `DLAN`.

Particle and soft-body attributes¶

Attribute	Description
`particle_enable_self_contact`	Enable particle self-contact.
`particle_self_contact_radius`	Particle radius used by self-contact.
`particle_self_contact_margin`	Detection margin for particle self-contact.
`particle_self_contact_mu`	Particle self-contact friction override; the negative default uses model material data.
`particle_contact_sleep_speed`	Low-speed threshold used by particle contact handling.
`particle_conservative_bound_relaxation`	Relaxation applied to conservative motion bounds.
`particle_vertex_contact_buffer_size`	Per-particle vertex-contact buffer capacity.
`particle_edge_contact_buffer_size`	Per-particle edge-contact buffer capacity.
`particle_collision_detection_interval`	Interval control for particle collision detection.
`particle_enable_tile_solve`	Enable the tiled particle solve path.
`particle_edge_parallel_epsilon`	Parallelism tolerance for edge contact tests.
`particle_topological_contact_filter_threshold`	Topological-neighborhood depth excluded from self-contact.
`particle_rest_shape_contact_exclusion_radius`	Rest-shape neighborhood excluded from self-contact.
`particle_external_vertex_contact_filtering_map`	Caller-provided vertex contact exclusions.
`particle_external_edge_contact_filtering_map`	Caller-provided edge contact exclusions.

Rigid AVBD and contact attributes¶

Attribute	Description
`rigid_avbd_alpha`	Shared AVBD penalty update factor.
`rigid_avbd_joint_alpha`	Joint-specific alpha override; the negative default uses `rigid_avbd_alpha`.
`rigid_avbd_contact_alpha`	Contact-specific alpha override; the negative default uses `rigid_avbd_alpha`.
`rigid_avbd_beta`	Shared AVBD beta value.
`rigid_avbd_linear_beta`	Linear beta override; the negative default uses `rigid_avbd_beta`.
`rigid_avbd_angular_beta`	Angular beta override; the negative default uses `rigid_avbd_beta`.
`rigid_avbd_gamma`	AVBD multiplier decay factor.
`rigid_contact_hard`	Select hard rigid contact constraints.
`rigid_contact_history`	Enable persistent rigid contact history.
`rigid_contact_stick_motion_eps`	Motion threshold for sticking contact history.
`rigid_contact_stick_freeze_translation_eps`	Translation threshold for freezing a sticking contact.
`rigid_contact_stick_freeze_angular_eps`	Angular threshold for freezing a sticking contact.
`rigid_contact_k_start`	Initial rigid contact penalty.
`rigid_body_contact_buffer_size`	Per-rigid-body contact buffer capacity.
`rigid_body_particle_contact_buffer_size`	Per-rigid-body particle-contact buffer capacity.

Rigid joint attributes¶

Attribute	Description
`rigid_joint_linear_ke`	Linear joint stiffness.
`rigid_joint_angular_ke`	Angular joint stiffness.
`rigid_joint_linear_k_start`	Initial linear joint penalty.
`rigid_joint_angular_k_start`	Initial angular joint penalty.
`rigid_joint_linear_kd`	Linear joint damping.
`rigid_joint_angular_kd`	Angular joint damping.

Example¶

import novaphy

builder = novaphy.ModelBuilder()
# ... add bodies, joints, shapes, or particles ...
builder.color()
model = builder.finalize()

cfg = novaphy.solvers.SolverVBD.Config()
cfg.iterations = 4
solver = novaphy.solvers.SolverVBD(model, cfg)

state = model.state()
control = model.control()
pipeline = novaphy.CollisionPipeline(model)
contacts = pipeline.contacts()
dt = 1.0 / 60.0

for _ in range(120):
    state.clear_forces()
    pipeline.collide(state, contacts)
    solver.step(state, state, control, contacts, dt)

Call novaphy.has_vbd_cuda() or novaphy.has_vbd_dlan() before selecting an optional backend.