Collision Constraints¶

Collision Constraints¶

class ipctk.CollisionConstraints¶

Bases: pybind11_object

Public Data Attributes:

use_convergent_formulation	If the collision constraints should use the convergent formulation.
are_shape_derivatives_enabled	If the collision constraints are using the convergent formulation.
vv_constraints
ev_constraints
ee_constraints
fv_constraints
pv_constraints

Public Methods:

__init__(self)
build(*args, **kwargs)	Overloaded function.
compute_potential(self, mesh, vertices, n]], ...)	Compute the barrier potential for a given constraint set.
compute_potential_gradient(self, mesh, ...)	Compute the gradient of the barrier potential.
compute_potential_hessian(self, mesh, ...)	Compute the hessian of the barrier potential.
compute_shape_derivative(self, mesh, ...)	Compute the barrier shape derivative.
compute_minimum_distance(self, mesh, ...)	Computes the minimum distance between any non-adjacent elements.
__len__(self)	Get the number of collision constraints.
empty(self)	Get if the collision constraints are empty.
clear(self)	Clear the collision constraints.
__getitem__(self, idx)	Get a reference to constriant idx.
is_vertex_vertex(self, idx)	Get if the constraint at idx is a vertex-vertex constraint.
is_edge_vertex(self, idx)	Get if the constraint at idx is an edge-vertex constraint.
is_edge_edge(self, idx)	Get if the constraint at idx is an edge-edge constraint.
is_face_vertex(self, idx)	Get if the constraint at idx is an face-vertex constraint.
is_plane_vertex(self, idx)	Get if the constraint at idx is an plane-vertex constraint.
to_string(*args, **kwargs)	Overloaded function.

Inherited from pybind11_object

---

__annotations__ = {}¶

__getitem__(self, idx: int) → ipctk.CollisionConstraint¶

Get a reference to constriant idx.

Parameters:¶

idx: int¶

The index of the constraint.

Returns:¶

A reference to the constraint.

__init__(self)¶

__len__(self) → int¶

Get the number of collision constraints.

__module__ = 'ipctk'¶

property are_shape_derivatives_enabled : bool¶

If the collision constraints are using the convergent formulation.

build(*args, **kwargs)¶

Overloaded function.

1. build(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]], dhat: float, dmin: float = 0, broad_phase_method: ipctk.BroadPhaseMethod = <BroadPhaseMethod.HASH_GRID: 1>) -> None

   Initialize the set of constraints used to compute the barrier potential.

   Parameters:

   mesh: The collision mesh. vertices: Vertices of the collision mesh. dhat: The activation distance of the barrier. dmin: Minimum distance. broad_phase_method: Broad-phase method to use.

2. build(self: ipctk.CollisionConstraints, candidates: ipctk.Candidates, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]], dhat: float, dmin: float = 0) -> None

   Initialize the set of constraints used to compute the barrier potential.

   Parameters:

   candidates: Distance candidates from which the constraint set is built. mesh: The collision mesh. vertices: Vertices of the collision mesh. dhat: The activation distance of the barrier. dmin: Minimum distance.

clear(self) → None¶

Clear the collision constraints.

compute_minimum_distance(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]]) → float¶

Computes the minimum distance between any non-adjacent elements.

Parameters:¶

mesh

The collision mesh.

vertices

Vertices of the collision mesh.

Returns:¶

The minimum distance between any non-adjacent elements.

compute_potential(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]], dhat: float) → float¶

Compute the barrier potential for a given constraint set.

Parameters:¶

mesh

The collision mesh.

vertices

Vertices of the collision mesh.

dhat

The activation distance of the barrier.

Returns:¶

The sum of all barrier potentials (not scaled by the barrier stiffness).

compute_potential_gradient(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]], dhat: float) → numpy.ndarray[numpy.float64[m, 1]]¶

Compute the gradient of the barrier potential.

Parameters:¶

mesh

The collision mesh.

vertices

Vertices of the collision mesh.

dhat

The activation distance of the barrier.

Returns:¶

The gradient of all barrier potentials (not scaled by the barrier stiffness). This will have a size of |vertices|.

compute_potential_hessian(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]], dhat: float, project_hessian_to_psd: bool = False) → scipy.sparse.csc_matrix[numpy.float64]¶

Compute the hessian of the barrier potential.

Parameters:¶

mesh

The collision mesh.

vertices

Vertices of the collision mesh.

dhat

The activation distance of the barrier.

project_hessian_to_psd

Make sure the hessian is positive semi-definite.

Returns:¶

The hessian of all barrier potentials (not scaled by the barrier stiffness). This will have a size of |vertices|x|vertices|.

compute_shape_derivative(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]], dhat: float) → scipy.sparse.csc_matrix[numpy.float64]¶

Compute the barrier shape derivative.

std::runtime_error If the collision constraints were not built with shape derivatives enabled.

Parameters:¶

mesh

The collision mesh.

vertices

Vertices of the collision mesh.

dhat

The activation distance of the barrier.

Returns:¶

The derivative of the force with respect to X, the rest vertices.

property ee_constraints : list[ipc::EdgeEdgeConstraint]¶

empty(self) → bool¶

Get if the collision constraints are empty.

property ev_constraints : list[ipc::EdgeVertexConstraint]¶

property fv_constraints : list[ipc::FaceVertexConstraint]¶

is_edge_edge(self, idx: int) → bool¶

Get if the constraint at idx is an edge-edge constraint.

Parameters:¶

idx: int¶

The index of the constraint.

Returns:¶

If the constraint at idx is an edge-edge constraint.

is_edge_vertex(self, idx: int) → bool¶

Get if the constraint at idx is an edge-vertex constraint.

Parameters:¶

idx: int¶

The index of the constraint.

Returns:¶

If the constraint at idx is an edge-vertex constraint.

is_face_vertex(self, idx: int) → bool¶

Get if the constraint at idx is an face-vertex constraint.

Parameters:¶

idx: int¶

The index of the constraint.

Returns:¶

If the constraint at idx is an face-vertex constraint.

is_plane_vertex(self, idx: int) → bool¶

Get if the constraint at idx is an plane-vertex constraint.

Parameters:¶

idx: int¶

The index of the constraint.

Returns:¶

If the constraint at idx is an plane-vertex constraint.

is_vertex_vertex(self, idx: int) → bool¶

Get if the constraint at idx is a vertex-vertex constraint.

Parameters:¶

idx: int¶

The index of the constraint.

Returns:¶

If the constraint at idx is a vertex-vertex constraint.

property pv_constraints : list[ipc::PlaneVertexConstraint]¶

to_string(*args, **kwargs)¶

Overloaded function.

1. to_string(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]]) -> str

2. to_string(self: ipctk.CollisionConstraints, mesh: ipc::CollisionMesh, vertices: numpy.ndarray[numpy.float64[m, n]]) -> str

property use_convergent_formulation : bool¶

If the collision constraints should use the convergent formulation.

property vv_constraints : list[ipc::VertexVertexConstraint]¶

Collision Constraint¶

class ipctk.CollisionConstraint¶

Bases: CollisionStencil

Public Data Attributes:

dmin
weight
weight_gradient

Public Methods:

__init__(*args, **kwargs)
compute_potential(self, vertices, edges, ...)
compute_potential_gradient(self, vertices, ...)
compute_potential_hessian(self, vertices, ...)
compute_shape_derivative(self, ...)	Compute the derivative of the potential gradient wrt the shape.

Inherited from CollisionStencil

__init__(*args, **kwargs)
num_vertices(self)	Get the number of vertices in the contact stencil.
vertex_ids(self, edges, faces)	Get the vertex IDs of the contact stencil.
vertices(self, vertices, edges, faces)	Get the vertex attributes of the contact stencil.
dof(self, X, edges, faces)	Select this stencil's DOF from the full matrix of DOF.
compute_distance(self, vertices, edges, faces)	Compute the distance of the stencil.
compute_distance_gradient(self, vertices, ...)	Compute the distance gradient of the stencil w.r.t.
compute_distance_hessian(self, vertices, ...)	Compute the distance Hessian of the stencil w.r.t.

Inherited from pybind11_object

---

__annotations__ = {}¶

__init__(*args, **kwargs)¶

__module__ = 'ipctk'¶

compute_potential(self, vertices: numpy.ndarray[numpy.float64[m, n]], edges: numpy.ndarray[numpy.int32[m, n]], faces: numpy.ndarray[numpy.int32[m, n]], dhat: float) → float¶

compute_potential_gradient(self, vertices: numpy.ndarray[numpy.float64[m, n]], edges: numpy.ndarray[numpy.int32[m, n]], faces: numpy.ndarray[numpy.int32[m, n]], dhat: float) → numpy.ndarray[numpy.float64[m, 1]]¶

compute_potential_hessian(self, vertices: numpy.ndarray[numpy.float64[m, n]], edges: numpy.ndarray[numpy.int32[m, n]], faces: numpy.ndarray[numpy.int32[m, n]], dhat: float, project_hessian_to_psd: bool) → numpy.ndarray[numpy.float64[m, n]]¶

compute_shape_derivative(self, rest_positions: numpy.ndarray[numpy.float64[m, n]], vertices: numpy.ndarray[numpy.float64[m, n]], edges: numpy.ndarray[numpy.int32[m, n]], faces: numpy.ndarray[numpy.int32[m, n]], dhat: float) → List[Eigen::Triplet<double, int>]¶

Compute the derivative of the potential gradient wrt the shape.

property dmin : float¶

property weight : float¶

property weight_gradient : scipy.sparse.csc_matrix[numpy.float64]¶

Vertex-Vertex Collision Constraint¶

class ipctk.VertexVertexConstraint¶

Bases: VertexVertexCandidate, CollisionConstraint

Public Data Attributes:

Inherited from VertexVertexCandidate

vertex0_id	ID of the first vertex
vertex1_id	ID of the second vertex

Inherited from CollisionConstraint

dmin
weight
weight_gradient

Public Methods:

__init__(*args, **kwargs)

Overloaded function.

Inherited from VertexVertexCandidate

__init__(self, vertex0_id, vertex1_id)
__str__(self)
__repr__(self)
__eq__(self, other)
__ne__(self, other)
__lt__(self, other)	Compare EdgeVertexCandidates for sorting.

Inherited from CollisionConstraint

__init__(*args, **kwargs)
compute_potential(self, vertices, edges, ...)
compute_potential_gradient(self, vertices, ...)
compute_potential_hessian(self, vertices, ...)
compute_shape_derivative(self, ...)	Compute the derivative of the potential gradient wrt the shape.

Inherited from CollisionStencil

__init__(*args, **kwargs)
num_vertices(self)	Get the number of vertices in the contact stencil.
vertex_ids(self, edges, faces)	Get the vertex IDs of the contact stencil.
vertices(self, vertices, edges, faces)	Get the vertex attributes of the contact stencil.
dof(self, X, edges, faces)	Select this stencil's DOF from the full matrix of DOF.
compute_distance(self, vertices, edges, faces)	Compute the distance of the stencil.
compute_distance_gradient(self, vertices, ...)	Compute the distance gradient of the stencil w.r.t.
compute_distance_hessian(self, vertices, ...)	Compute the distance Hessian of the stencil w.r.t.

Inherited from ContinuousCollisionCandidate

__init__(*args, **kwargs)
ccd(self, vertices_t0, vertices_t1, edges, faces)	Perform narrow-phase CCD on the candidate.
print_ccd_query(self, vertices_t0, ...)	Print the CCD query to cout.

Inherited from pybind11_object

---

__annotations__ = {}¶

__init__(*args, **kwargs)¶

Overloaded function.

1. __init__(self: ipctk.VertexVertexConstraint, vertex0_id: int, vertex1_id: int) -> None

2. __init__(self: ipctk.VertexVertexConstraint, vv_candidate: ipctk.VertexVertexCandidate) -> None

__module__ = 'ipctk'¶

Edge-Vertex Collision Constraint¶

class ipctk.EdgeVertexConstraint¶

Bases: EdgeVertexCandidate, CollisionConstraint

Public Data Attributes:

Inherited from EdgeVertexCandidate

edge_id	ID of the edge
vertex_id	ID of the vertex

Inherited from CollisionConstraint

dmin
weight
weight_gradient

Public Methods:

__init__(*args, **kwargs)

Overloaded function.

Inherited from EdgeVertexCandidate

__init__(self, edge_id, vertex_id)
__str__(self)
__repr__(self)
__eq__(self, other)
__ne__(self, other)
__lt__(self, other)	Compare EdgeVertexCandidates for sorting.

Inherited from CollisionConstraint

__init__(*args, **kwargs)
compute_potential(self, vertices, edges, ...)
compute_potential_gradient(self, vertices, ...)
compute_potential_hessian(self, vertices, ...)
compute_shape_derivative(self, ...)	Compute the derivative of the potential gradient wrt the shape.

Inherited from CollisionStencil

__init__(*args, **kwargs)
num_vertices(self)	Get the number of vertices in the contact stencil.
vertex_ids(self, edges, faces)	Get the vertex IDs of the contact stencil.
vertices(self, vertices, edges, faces)	Get the vertex attributes of the contact stencil.
dof(self, X, edges, faces)	Select this stencil's DOF from the full matrix of DOF.
compute_distance(self, vertices, edges, faces)	Compute the distance of the stencil.
compute_distance_gradient(self, vertices, ...)	Compute the distance gradient of the stencil w.r.t.
compute_distance_hessian(self, vertices, ...)	Compute the distance Hessian of the stencil w.r.t.

Inherited from ContinuousCollisionCandidate

__init__(*args, **kwargs)
ccd(self, vertices_t0, vertices_t1, edges, faces)	Perform narrow-phase CCD on the candidate.
print_ccd_query(self, vertices_t0, ...)	Print the CCD query to cout.

Inherited from pybind11_object

---

__annotations__ = {}¶

__init__(*args, **kwargs)¶

Overloaded function.

1. __init__(self: ipctk.EdgeVertexConstraint, edge_id: int, vertex_id: int) -> None

2. __init__(self: ipctk.EdgeVertexConstraint, candidate: ipctk.EdgeVertexCandidate) -> None

__module__ = 'ipctk'¶

Edge-Edge Collision Constraint¶

class ipctk.EdgeEdgeConstraint¶

Bases: EdgeEdgeCandidate, CollisionConstraint

Public Data Attributes:

eps_x	Mollifier activation threshold.
dtype	Cached distance type.

Inherited from EdgeEdgeCandidate

edge0_id	ID of the first edge.
edge1_id	ID of the second edge.

Inherited from CollisionConstraint

dmin
weight
weight_gradient

Public Methods:

__init__(*args, **kwargs)	Overloaded function.
__eq__(self, other)
__ne__(self, other)
__lt__(self, other)

Inherited from EdgeEdgeCandidate

__init__(self, edge0_id, edge1_id)
__str__(self)
__repr__(self)
__eq__(self, other)
__ne__(self, other)
__lt__(self, other)	Compare EdgeEdgeCandidates for sorting.

Inherited from CollisionConstraint

__init__(*args, **kwargs)
compute_potential(self, vertices, edges, ...)
compute_potential_gradient(self, vertices, ...)
compute_potential_hessian(self, vertices, ...)
compute_shape_derivative(self, ...)	Compute the derivative of the potential gradient wrt the shape.

Inherited from CollisionStencil

__init__(*args, **kwargs)
num_vertices(self)	Get the number of vertices in the contact stencil.
vertex_ids(self, edges, faces)	Get the vertex IDs of the contact stencil.
vertices(self, vertices, edges, faces)	Get the vertex attributes of the contact stencil.
dof(self, X, edges, faces)	Select this stencil's DOF from the full matrix of DOF.
compute_distance(self, vertices, edges, faces)	Compute the distance of the stencil.
compute_distance_gradient(self, vertices, ...)	Compute the distance gradient of the stencil w.r.t.
compute_distance_hessian(self, vertices, ...)	Compute the distance Hessian of the stencil w.r.t.

Inherited from ContinuousCollisionCandidate

__init__(*args, **kwargs)
ccd(self, vertices_t0, vertices_t1, edges, faces)	Perform narrow-phase CCD on the candidate.
print_ccd_query(self, vertices_t0, ...)	Print the CCD query to cout.

Inherited from pybind11_object

---

__annotations__ = {}¶

__eq__(self, other: ipctk.EdgeEdgeConstraint) → bool¶

__hash__ = None¶

__init__(*args, **kwargs)¶

Overloaded function.

1. __init__(self: ipctk.EdgeEdgeConstraint, edge0_id: int, edge1_id: int, eps_x: float, dtype: ipctk.EdgeEdgeDistanceType = <EdgeEdgeDistanceType.AUTO: 9>) -> None

2. __init__(self: ipctk.EdgeEdgeConstraint, candidate: ipctk.EdgeEdgeCandidate, eps_x: float, dtype: ipctk.EdgeEdgeDistanceType = <EdgeEdgeDistanceType.AUTO: 9>) -> None

__lt__(self, other: ipctk.EdgeEdgeConstraint) → bool¶

__module__ = 'ipctk'¶

__ne__(self, other: ipctk.EdgeEdgeConstraint) → bool¶

property dtype : ipctk.EdgeEdgeDistanceType¶

Cached distance type.

Some EE constraints are mollified EV or VV constraints.

property eps_x : float¶

Mollifier activation threshold.

Face-Vertex Collision Constraint¶

class ipctk.FaceVertexConstraint¶

Bases: FaceVertexCandidate, CollisionConstraint

Public Data Attributes:

Inherited from FaceVertexCandidate

face_id	ID of the face
vertex_id	ID of the vertex

Inherited from CollisionConstraint

dmin
weight
weight_gradient

Public Methods:

__init__(*args, **kwargs)

Overloaded function.

Inherited from FaceVertexCandidate

__init__(self, face_id, vertex_id)
__str__(self)
__repr__(self)
__eq__(self, other)
__ne__(self, other)
__lt__(self, other)	Compare FaceVertexCandidate for sorting.

Inherited from CollisionConstraint

__init__(*args, **kwargs)
compute_potential(self, vertices, edges, ...)
compute_potential_gradient(self, vertices, ...)
compute_potential_hessian(self, vertices, ...)
compute_shape_derivative(self, ...)	Compute the derivative of the potential gradient wrt the shape.

Inherited from CollisionStencil

__init__(*args, **kwargs)
num_vertices(self)	Get the number of vertices in the contact stencil.
vertex_ids(self, edges, faces)	Get the vertex IDs of the contact stencil.
vertices(self, vertices, edges, faces)	Get the vertex attributes of the contact stencil.
dof(self, X, edges, faces)	Select this stencil's DOF from the full matrix of DOF.
compute_distance(self, vertices, edges, faces)	Compute the distance of the stencil.
compute_distance_gradient(self, vertices, ...)	Compute the distance gradient of the stencil w.r.t.
compute_distance_hessian(self, vertices, ...)	Compute the distance Hessian of the stencil w.r.t.

Inherited from ContinuousCollisionCandidate

__init__(*args, **kwargs)
ccd(self, vertices_t0, vertices_t1, edges, faces)	Perform narrow-phase CCD on the candidate.
print_ccd_query(self, vertices_t0, ...)	Print the CCD query to cout.

Inherited from pybind11_object

---

__annotations__ = {}¶

__init__(*args, **kwargs)¶

Overloaded function.

1. __init__(self: ipctk.FaceVertexConstraint, face_id: int, vertex_id: int) -> None

2. __init__(self: ipctk.FaceVertexConstraint, candidate: ipctk.FaceVertexCandidate) -> None

__module__ = 'ipctk'¶

Plane-Vertex Collision Constraint¶

class ipctk.PlaneVertexConstraint¶

Bases: CollisionConstraint

Public Data Attributes:

plane_origin
plane_normal
vertex_id

Inherited from CollisionConstraint

dmin
weight
weight_gradient

Public Methods:

__init__(self, plane_origin, plane_normal, ...)

Inherited from CollisionConstraint

__init__(*args, **kwargs)
compute_potential(self, vertices, edges, ...)
compute_potential_gradient(self, vertices, ...)
compute_potential_hessian(self, vertices, ...)
compute_shape_derivative(self, ...)	Compute the derivative of the potential gradient wrt the shape.

Inherited from CollisionStencil

__init__(*args, **kwargs)
num_vertices(self)	Get the number of vertices in the contact stencil.
vertex_ids(self, edges, faces)	Get the vertex IDs of the contact stencil.
vertices(self, vertices, edges, faces)	Get the vertex attributes of the contact stencil.
dof(self, X, edges, faces)	Select this stencil's DOF from the full matrix of DOF.
compute_distance(self, vertices, edges, faces)	Compute the distance of the stencil.
compute_distance_gradient(self, vertices, ...)	Compute the distance gradient of the stencil w.r.t.
compute_distance_hessian(self, vertices, ...)	Compute the distance Hessian of the stencil w.r.t.

Inherited from pybind11_object

---

__annotations__ = {}¶

__init__(self, plane_origin: numpy.ndarray[numpy.float64[m, 1]], plane_normal: numpy.ndarray[numpy.float64[m, 1]], vertex_id: int)¶

__module__ = 'ipctk'¶

property plane_normal : numpy.ndarray[numpy.float64[m, 1]]¶

property plane_origin : numpy.ndarray[numpy.float64[m, 1]]¶

property vertex_id : int¶