netdem::LevelSet Class Reference

A class for representing a level set function as a Shape object. More...

#include <shape_level_set.hpp>

Inheritance diagram for netdem::LevelSet:

Public Member Functions
	LevelSet ()
	Default constructor.
nlohmann::json	PackJson () override
	Pack the LevelSet object into a JSON structure.
void	InitFromJson (nlohmann::json const &js) override
	Initialize the LevelSet object from a JSON structure.
void	InitFromSTL (std::string const &file, int mesh_res=40)
	Initialize the LevelSet object from an STL file.
void	InitFromSTL (STLModel const &stl_model, int mesh_res=40)
	Initialize the LevelSet object from an STL model.
void	InitFromDistanceMap (double c_0, double c_1, double c_2, double sp, const VecXT< VecXT< VecXT< double > > > &dist_map)
	Initialize the LevelSet object from a distance map.
void	Init ()
	Initialize the LevelSet object.
void	AlignAxes ()
	Align the axes of the LevelSet object.
void	UpdateSurfaceNodes () override
	Update the surface nodes of the LevelSet object.
void	UpdateShapeProperties () override
	Update the shape properties of the LevelSet object.
void	SetSize (double d) override
	Set the size of the LevelSet object.
Shape *	Clone () const override
	Clone the LevelSet object.
STLModel	GetSTLModel (int num_nodes=200) override
	Generate an STL model of the LevelSet object.
double	SignedDistance (Vec3d const &pos) const override
	Compute the signed distance from a given position to the surface of the LevelSet object.
Vec3d	SurfacePoint (Vec3d const &pos) override
	Compute the surface point closest to a given position on the LevelSet object.
void	Print () override
	Print information about the LevelSet object.
Public Member Functions inherited from netdem::LevelSetFunction
	LevelSetFunction ()
	Default constructor.
Vec3d const &	GetCorner () const
double	GetSpacing () const
Vec3i const &	GetDimensions () const
double	GetSignedDistance (int id_x, int id_y, int id_z)
	Get the signed distance value of a certian cell of the grid.
VecXT< VecXT< VecXT< double > > > const &	GetSignedDistanceTable () const
void	SetCorner (double corner_x, double corner_y, double corner_z)
	Set the corner of the grid.
void	SetSpacing (double sp)
	Set the spacing between grid points.
void	SetDimension (double dim_x, double dim_y, double dim_z)
	Set the dimensions of the grid.
void	SetSignedDistance (int id_x, int id_y, int id_z, double sdf)
	Set the signed distance value of a certian cell of the grid.
void	InitFromSDFCalculator (const SDFCalculator &sdf_calculator)
	Initialize from a signed distance field.
double	SignedDistance (Vec3d const &pos) const
	Compute the signed distance at a point in space.
Vec3d	GradientInterpolate (Vec3d const &pos)
	Compute the gradient at a point in space using interpolation.
Vec3d	GradientMinus (int i, int j, int k)
	Compute the gradient at the grid point (i, j, k) using backward differences.
Vec3d	GradientPlus (int i, int j, int k)
	Compute the gradient at the grid point (i, j, k) using forward differences.
void	Reinitialization (int iter, double dt)
	Perform reinitialization to maintain properties of the level set function.
void	Reinitialization ()
	Perform reinitialization with default parameters.
Public Member Functions inherited from netdem::Shape
virtual void	InitFromJsonFile (std::string const &js_file)
	Initializes the shape instance from a JSON file.
virtual double	GetSize () const
	Return shape size, which is defined as the diameter of equal-volume sphere.
virtual double	GetVolume () const
	Return the volume of the shape.
virtual Mat3d const &	GetInertia () const
	Return the inertia of the shape.
Vec3d	GetInertiaPrincipal () const
	Return the principal inertia of the shape.
virtual double	GetBoundSphereRadius () const
	Return the inertia of the shape.
virtual std::tuple< Vec3d, Vec3d >	GetBoundAABB () const
	Gets the boundary AABB of the shape instance.
virtual std::tuple< Vec3d, Vec3d >	GetBoundAABB (Vec3d const &pos, Vec4d const &quat) const
	Gets the boundary AABB of the shape instance.
virtual double	GetSkin () const
	Return skin size of the shape.
virtual double	GetSkinFactor () const
	Return skin factor of the shape.
virtual double	GetSurfaceNodeNum () const
	Return number of surface nodes of the shape.
virtual VecXT< Vec3d > const &	GetSurfaceNodes () const
	Return surface nodes of the shape.
virtual VecXT< double > const &	GetSurfaceNodeAreas () const
	Return surface area associated with each surface node.
virtual double	GetSurfaceNodeSpacing () const
	Return spacing of surface nodes.
const STLModel &	GetRenderMesh () const
	Return the surface mesh for rendering.
bool	CheckConvexity ()
	Return the convexity of the shape.
virtual void	Translate (Vec3d const &pos)
	Translates the shape instance to a new position.
virtual void	UpdateRenderMesh (int num_nodes=200)
	Initializes the surface mesh for rendering.
virtual void	SetSkin (double sk)
	Set skin size of the shape.
virtual void	SetSkinFactor (double sk_factor)
	Set skin size factor (skin = size by skin size factor) of the shape.
virtual void	EnableSurfaceNodes ()
	Enable the use of surface nodes.
virtual void	DisableSurfaceNodes ()
	Disable the use of surface nodes.
virtual bool	IsSurfaceNodesEnabled ()
	Check if the use of surface nodes is enabled.
virtual void	SetSurfaceNodeNum (int num)
	Set number of surface nodes of the shape.
virtual void	SetSurfaceNodes (VecXT< Vec3d > const &nodes)
	Set the surface nodes of the shape.
virtual void	SetSurfaceNodes (STLModel const &surf_stl)
	Set the surface nodes of the shape.
virtual void	SaveAsVTK (std::string const &filename)
	Saves the shape instance as a VTK file.
virtual void	SaveAsSTL (std::string const &filename)
	Saves the shape instance as an STL file.
virtual Vec3d	SupportPoint (Vec3d const &dir)
	Gets the support point in a given direction for the shape instance.
virtual VecXT< Vec3d >	SupportPoints (Vec3d const &dir)
	Gets the set of support points in a given direction for the shape instance.
virtual bool	CheckEnclose (Vec3d const &pos) const
	Determines whether a given point is enclosed within the shape instance.
virtual bool	CheckPrincipal () const
	Determines whether the shape is in principal configuration.
virtual	~Shape ()
	Destructor for the Shape class.

Additional Inherited Members
Public Types inherited from netdem::Shape
enum	Type {   none , point_sphere , sphere , spherical_harmonics ,   trimesh , trimesh_convex , ellipsoid , polybezier ,   triangle , plane , cylinder , poly_super_ellipsoid ,   poly_super_quadrics , level_set , netsdf , coded_netsdf ,   num_shapes }
	Enumeration for different types of shapes. More...
Static Public Member Functions inherited from netdem::Shape
static MatNd< 8, 3 >	VerticesOfAABB (Vec3d const &bmin, Vec3d const &bmax)
	Gets the vertices of the boundary AABB of the shape instance.
Public Attributes inherited from netdem::Shape
int	id {0}
	ID of the shape instance.
std::string	label {"default"}
	Label of the shape instance.
Type	shape_type {Type::none}
	Type of the shape instance.
std::string	shape_name {"shape"}
	Name of the shape instance.
bool	use_customized_solver {false}
	Determines whether to use a customized contact solver or not.
STLModel	render_mesh
	Surface mesh for rendering.
Protected Attributes inherited from netdem::LevelSetFunction
Vec3d	corner {-0.5, -0.5, -0.5}
	Coordinates of the corner of the grid.
double	spacing {0.05}
	Spacing between grid points.
Vec3i	dim {21, 21, 21}
	Dimensions of the grid.
VecXT< VecXT< VecXT< double > > >	signed_distance_table
	Table containing the signed distance values.
Protected Attributes inherited from netdem::Shape
double	size {1.0}
	Size and volume of the shape instance.
double	volume {0.5236}
	Volume of the shape instance.
Mat3d	inertia {{{0.05236, 0, 0}, {0, 0.05236, 0}, {0, 0, 0.05236}}}
	Inertia tensor of the shape instance.
double	bound_sphere_radius {0.5}
	Radius of the bounding sphere used for broad-phase contact detection.
double	skin {0.025}
	Skin thickness used for broad-phase contact detection.
double	skin_factor {0.05}
	Factor used to adjust the skin thickness.
Vec3d	bound_aabb_min {-0.5, -0.5, -0.5}
	Minimum bounds of the AABB used for broad-phase contact detection.
Vec3d	bound_aabb_max {0.5, 0.5, 0.5}
	Maximum bounds of the AABB used for broad-phase contact detection.
bool	is_convex {true}
	Determines whether the shape instance is convex or not.
bool	use_surface_nodes {false}
	Determines whether to use nodes for the contact solver.
int	surface_node_num {1000}
	Number of nodes used for the contact solver.
double	surface_node_spacing {std::sqrt(Math::PI / 1000.0)}
	Spacing between nodes used for the contact solver.
VecXT< Vec3d >	surface_nodes
	Surface nodes of the shape instance used for the contact solver.
VecXT< double >	surface_node_areas
	Area associated with each surface node.

Detailed Description

A class for representing a level set function as a Shape object.

This class provides methods for initializing a level set function from an STL file or distance map, computing signed distances and surface points, and generating STL models for visualization.

Additionally, the LevelSet class is a subclass of the Shape class, which allows it to be used in combination with other shapes in compound objects.

Examples

00_sdf_demo.cpp, and 90_packing_demo.cpp.

Constructor & Destructor Documentation

LevelSet()

LevelSet::LevelSet

(

)

Default constructor.

Member Function Documentation

AlignAxes()

void LevelSet::AlignAxes

(

)

Align the axes of the LevelSet object.

This method aligns the axes of the LevelSet object with the principal components of its surface points.

Examples

90_packing_demo.cpp.

Clone()

Shape * LevelSet::Clone ( ) const

overridevirtual

Clone the LevelSet object.

This method creates a copy of the LevelSet object.

Returns

A pointer to the cloned LevelSet object.

Reimplemented from netdem::Shape.

GetSTLModel()

STLModel LevelSet::GetSTLModel ( int num_nodes = 200 )

overridevirtual

Generate an STL model of the LevelSet object.

This method generates an STL model of the LevelSet object using the specified number of nodes for each surface triangle.

Parameters

num_nodes

The number of nodes to use for each surface triangle (default: 200).

Returns

An STLModel object representing the LevelSet object.

Reimplemented from netdem::Shape.

Init()

void LevelSet::Init

(

)

Initialize the LevelSet object.

This method initializes the LevelSet object by aligning its axes and updating its nodes and shape properties.

InitFromDistanceMap()

void LevelSet::InitFromDistanceMap	(	double	c_0,
		double	c_1,
		double	c_2,
		double	sp,
		const VecXT< VecXT< VecXT< double > > > &	dist_map )

Initialize the LevelSet object from a distance map.

This method initializes the LevelSet object from a distance map computed externally.

Parameters

c_0	The x coordinate of the center of the bounding box containing the distance map.
c_1	The y coordinate of the center of the bounding box containing the distance map.
c_2	The z coordinate of the center of the bounding box containing the distance map.
sp	The spacing between grid points in the distance map.
dist_map	The distance map as a 3D array of double values.

InitFromJson()

void LevelSet::InitFromJson ( nlohmann::json const & js )

overridevirtual

Initialize the LevelSet object from a JSON structure.

This method initializes the LevelSet object from a JSON structure previously generated by PackJson().

Parameters

js	The JSON structure to load.

Reimplemented from netdem::Shape.

InitFromSTL() [1/2]

void netdem::LevelSet::InitFromSTL	(	std::string const &	file,
		int	mesh_res = 40 )

Initialize the LevelSet object from an STL file.

This method initializes the LevelSet object from an STL file by converting it to a distance map and then computing its level set function.

Parameters

file	The name of the STL file to load.
mesh_res	The resolution of the mesh used in the conversion to a distance map (default: 40).

Examples

90_packing_demo.cpp.

InitFromSTL() [2/2]

void LevelSet::InitFromSTL	(	STLModel const &	stl_model,
		int	mesh_res = 40 )

Initialize the LevelSet object from an STL model.

This method initializes the LevelSet object from an STL model by converting it to a distance map and then computing its level set function.

Parameters

stl_model	The STL model to load.
mesh_res	The resolution of the mesh used in the conversion to a distance map (default: 40).

PackJson()

nlohmann::json LevelSet::PackJson ( )

overridevirtual

Pack the LevelSet object into a JSON structure.

This method packs the LevelSet object into a JSON structure for serialization and storage.

Returns

The packed JSON structure.

Reimplemented from netdem::Shape.

Print()

void LevelSet::Print ( )

overridevirtual

Print information about the LevelSet object.

This method prints basic information about the LevelSet object, including its position, rotation, size, volume, and surface area.

Reimplemented from netdem::Shape.

SetSize()

void LevelSet::SetSize ( double d )

overridevirtual

Set the size of the LevelSet object.

This method sets the size of the LevelSet object by scaling it uniformly in all dimensions.

Parameters

d	The new size of the LevelSet object.

Reimplemented from netdem::Shape.

Examples

90_packing_demo.cpp.

SignedDistance()

double LevelSet::SignedDistance ( Vec3d const & pos ) const

overridevirtual

Compute the signed distance from a given position to the surface of the LevelSet object.

This method computes the signed distance from a given position to the surface of the LevelSet object by evaluating its level set function.

Parameters

pos	The position for which to compute the signed distance.

Returns

The signed distance from the specified position to the surface of the LevelSet object.

Reimplemented from netdem::Shape.

SurfacePoint()

Vec3d LevelSet::SurfacePoint ( Vec3d const & pos )

overridevirtual

Compute the surface point closest to a given position on the LevelSet object.

This method computes the surface point closest to a given position on the LevelSet object by finding the intersection of a line passing through the specified position and perpendicular to the level set surface with the level set surface.

Parameters

pos	The position for which to compute the closest surface point.

Returns

The surface point closest to the specified position on the LevelSet object.

Reimplemented from netdem::Shape.

UpdateShapeProperties()

void LevelSet::UpdateShapeProperties ( )

overridevirtual

Update the shape properties of the LevelSet object.

This method updates the shape properties of the LevelSet object, such as its volume and surface area.

Reimplemented from netdem::Shape.

UpdateSurfaceNodes()

void LevelSet::UpdateSurfaceNodes ( )

overridevirtual

Update the surface nodes of the LevelSet object.

This method updates the surface nodes of the LevelSet object based on its current position and rotation.

Reimplemented from netdem::Shape.

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The documentation for this class was generated from the following files:

• /Users/lzhshou/Documents/Research/myProjects/apaam/repo/netdem/src/shape/shape_level_set.hpp
• /Users/lzhshou/Documents/Research/myProjects/apaam/repo/netdem/src/shape/shape_level_set.cpp