A class for representing an ellipsoid shape. More...

#include <shape_ellipsoid.hpp>

Inheritance diagram for netdem::Ellipsoid:

Public Member Functions
	Ellipsoid ()
	Default constructor.

	Ellipsoid (double a, double b, double c)
	Constructor taking the lengths of the three semi-axes.

Shape *	Clone () const override
	Clone the Ellipsoid object.

nlohmann::json	PackJson () override
	Pack the Ellipsoid object into a JSON structure.

void	InitFromJson (nlohmann::json const &js) override
	Initialize the Ellipsoid object from a JSON structure.

void	Init ()
	Initialize the Ellipsoid object.

void	SetSize (double d) override
	Set the size of the Ellipsoid object.

void	UpdateSurfaceNodes () override
	Update the surface nodes of the Ellipsoid object.

void	UpdateShapeProperties () override
	Update the shape properties of the Ellipsoid object.

STLModel	GetSTLModel (int num_nodes=200) override
	Generate an STL model of the Ellipsoid object.

Vec3d	SupportPoint (Vec3d const &dir) override
	Compute the support point in a given direction for the Ellipsoid object.

VecXT< Vec3d >	SupportPoints (Vec3d const &dir) override
	Compute the support points in a given direction for the Ellipsoid object.

double	SignedDistance (Vec3d const &pos) const override
	Compute the signed distance from a given position to the surface of the Ellipsoid object.

Vec3d	SurfacePoint (Vec3d const &pos) override
	Compute the surface point closest to a given position on the Ellipsoid object.

double	CalculateRho (Vec3d const &dir) const
	Compute the distance from the center of the Ellipsoid object to a plane perpendicular to its axis in a given direction.

void	Print () override
	Print information about the Ellipsoid object.

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 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.

Public Attributes
double	axis_a {0.5}
	The length of the semi-axis in the x direction.

double	axis_b {0.5}
	The length of the semi-axis in the y direction.

double	axis_c {0.5}
	The length of the semi-axis in the z direction.

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.

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.

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 an ellipsoid shape.

This class provides methods for computing signed distances, surface points, support points, and STL models for an ellipsoid shape.

Examples: 0_demo_erosion_issue.cpp, 1_gjk_solver.cpp, 1_test_triaxial_comp.cpp, 20_gen_dataset_ellipsoid_plane.cpp, 21_test_dataset_ellipsoid_plane.cpp, 26_test_ann_vs_geom_ellipsoid_plane.cpp, 2_ev_gjk_performance.cpp, 2_sdf_solver.cpp, 30_gen_dataset_ellipsoid.cpp, 31_test_dataset_ellipsoid.cpp, 36_test_ann_vs_geom_ellipsoid.cpp, 37_test_ann_vs_geom_ellipsoid.cpp, 3_hybrid_solver.cpp, and 96_random_packing_ellipsoid.cpp.

Constructor & Destructor Documentation

◆ Ellipsoid() [1/2]

Ellipsoid::Ellipsoid ( )

Default constructor.

◆ Ellipsoid() [2/2]

Ellipsoid::Ellipsoid	(	double	a,
		double	b,
		double	c )

Constructor taking the lengths of the three semi-axes.

This constructor creates an ellipsoid with the specified lengths of its three semi-axes.

Parameters

a	The length of the semi-axis in the x direction.
b	The length of the semi-axis in the y direction.
c	The length of the semi-axis in the z direction.

Member Function Documentation

◆ CalculateRho()

double Ellipsoid::CalculateRho ( Vec3d const & dir ) const

Compute the distance from the center of the Ellipsoid object to a plane perpendicular to its axis in a given direction.

This private method computes the distance from the center of the Ellipsoid object to a plane perpendicular to its axis in a given direction, which is used when computing support points.

Parameters

dir	The direction of the plane.

Returns: The distance from the center of the Ellipsoid object to the plane.

◆ Clone()

Shape * Ellipsoid::Clone ( ) const

overridevirtual

Clone the Ellipsoid object.

This method creates a copy of the Ellipsoid object.

Returns: A pointer to the cloned Ellipsoid object.

Reimplemented from netdem::Shape.

◆ GetSTLModel()

STLModel Ellipsoid::GetSTLModel ( int num_nodes = 200 )

overridevirtual

Generate an STL model of the Ellipsoid object.

This method generates an STL model of the Ellipsoid 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 Ellipsoid object.

Reimplemented from netdem::Shape.

◆ Init()

void Ellipsoid::Init ( )

Initialize the Ellipsoid object.

This method initializes the Ellipsoid object by computing its initial surface points and updating its nodes.

◆ InitFromJson()

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

overridevirtual

Initialize the Ellipsoid object from a JSON structure.

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

Parameters

js	The JSON structure to load.

Reimplemented from netdem::Shape.

◆ PackJson()

nlohmann::json Ellipsoid::PackJson ( )

overridevirtual

Pack the Ellipsoid object into a JSON structure.

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

Returns: The packed JSON structure.

Reimplemented from netdem::Shape.

◆ Print()

void Ellipsoid::Print ( )

overridevirtual

Print information about the Ellipsoid object.

This method prints basic information about the Ellipsoid object, including its position, rotation, size, semi-axes lengths, volume, and surface area.

Reimplemented from netdem::Shape.

◆ SetSize()

void Ellipsoid::SetSize ( double d )

overridevirtual

Set the size of the Ellipsoid object.

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

Parameters

d	The new size of the Ellipsoid object.

Reimplemented from netdem::Shape.

Examples: 1_gjk_solver.cpp, 1_test_triaxial_comp.cpp, 20_gen_dataset_ellipsoid_plane.cpp, 21_test_dataset_ellipsoid_plane.cpp, 26_test_ann_vs_geom_ellipsoid_plane.cpp, 2_sdf_solver.cpp, 30_gen_dataset_ellipsoid.cpp, 31_test_dataset_ellipsoid.cpp, 36_test_ann_vs_geom_ellipsoid.cpp, 37_test_ann_vs_geom_ellipsoid.cpp, 3_hybrid_solver.cpp, and 96_random_packing_ellipsoid.cpp.

◆ SignedDistance()

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

overridevirtual

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

This method computes the signed distance from a given position to the surface of the Ellipsoid object by evaluating the implicit equation for an ellipsoid.

Parameters

pos	The position for which to compute the signed distance.

Returns: The signed distance from the specified position to the surface of the Ellipsoid object.

Reimplemented from netdem::Shape.

◆ SupportPoint()

Vec3d Ellipsoid::SupportPoint ( Vec3d const & dir )

overridevirtual

Compute the support point in a given direction for the Ellipsoid object.

This method computes the support point in a given direction for the Ellipsoid object by finding the point on its surface farthest in that direction.

Parameters

dir	The direction for which to compute the support point.

Returns: The support point in the specified direction for the Ellipsoid object.

Reimplemented from netdem::Shape.

Examples: 20_gen_dataset_ellipsoid_plane.cpp, 2_ev_gjk_performance.cpp, 30_gen_dataset_ellipsoid.cpp, and 37_test_ann_vs_geom_ellipsoid.cpp.

◆ SupportPoints()

VecXT< Vec3d > Ellipsoid::SupportPoints ( Vec3d const & dir )

overridevirtual

Compute the support points in a given direction for the Ellipsoid object.

This method computes the support points in a given direction for the Ellipsoid object by finding the two points on its top and bottom surfaces farthest in that direction.

Parameters

dir	The direction for which to compute the support points.

Returns: A vector of support points in the specified direction for the Ellipsoid object.

Reimplemented from netdem::Shape.

◆ SurfacePoint()

Vec3d Ellipsoid::SurfacePoint ( Vec3d const & pos )

overridevirtual

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

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

Parameters

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

Returns: The surface point closest to the specified position on the Ellipsoid object.

Reimplemented from netdem::Shape.

◆ UpdateShapeProperties()

void Ellipsoid::UpdateShapeProperties ( )

overridevirtual

Update the shape properties of the Ellipsoid object.

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

Reimplemented from netdem::Shape.

◆ UpdateSurfaceNodes()

void Ellipsoid::UpdateSurfaceNodes ( )

overridevirtual

Update the surface nodes of the Ellipsoid object.

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

Reimplemented from netdem::Shape.

Member Data Documentation

◆ axis_a

double netdem::Ellipsoid::axis_a {0.5}

The length of the semi-axis in the x direction.

◆ axis_b

double netdem::Ellipsoid::axis_b {0.5}

The length of the semi-axis in the y direction.

Examples: 0_demo_erosion_issue.cpp.

◆ axis_c

double netdem::Ellipsoid::axis_c {0.5}

The length of the semi-axis in the z direction.

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

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

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Ellipsoid() [1/2]

◆ Ellipsoid() [2/2]

Member Function Documentation

◆ CalculateRho()

◆ Clone()

◆ GetSTLModel()

◆ Init()

◆ InitFromJson()

◆ PackJson()

◆ Print()

◆ SetSize()

◆ SignedDistance()

◆ SupportPoint()

◆ SupportPoints()

◆ SurfacePoint()

◆ UpdateShapeProperties()

◆ UpdateSurfaceNodes()

Member Data Documentation

◆ axis_a

◆ axis_b

◆ axis_c