SignedDistancePair< T > Struct Template Reference

Detailed Description

template<typename T>
struct drake::geometry::SignedDistancePair< T >

The data for reporting the signed distance between two geometries, A and B.

It provides the id's of the two geometries, the witness points Ca and Cb on the surfaces of A and B, the signed distance, and nhat_BA_W a direction of fastest increasing distance (always unit length and always point outward from B's surface).

• When A and B are separated, distance > 0.
• When A and B are touching or penetrating, distance <= 0.
• By definition, nhat_AB_W must be in the opposite direction of nhat_BA_W.
• (p_WCa - p_Wcb) = distance · nhat_BA_W.

  Warning

  For two geometries that are just touching (i.e., distance = 0), the underlying code can guarantee a correct value for nhat_BA_W only when one geometry is a sphere, and the other geometry is a sphere, a box, or a cylinder. Otherwise, the underlying code is not in place yet to guarantee a correct value for nhat_BA_W when surfaces are just touching, and the vector will be populated by NaN values.

  Template Parameters

  T	The underlying scalar type. Must be a valid Eigen scalar.

#include <drake/geometry/query_results/signed_distance_pair.h>

Public Member Functions
	SignedDistancePair ()=default
	SignedDistancePair (GeometryId a, GeometryId b, const Vector3< T > &p_ACa_in, const Vector3< T > &p_BCb_in, const T &dist, const Vector3< T > &nhat_BA_W_in)
	Constructor.
void	SwapAAndB ()
	Swaps the interpretation of geometries A and B.
Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
	SignedDistancePair (const SignedDistancePair &)=default
SignedDistancePair &	operator= (const SignedDistancePair &)=default
	SignedDistancePair (SignedDistancePair &&)=default
SignedDistancePair &	operator= (SignedDistancePair &&)=default

Public Attributes
GeometryId	id_A
	The id of the first geometry in the pair.
GeometryId	id_B
	The id of the second geometry in the pair.
Vector3< T >	p_ACa
	The witness point on geometry A's surface, expressed in A's frame.
Vector3< T >	p_BCb
	The witness point on geometry B's surface, expressed in B's frame.
T	distance {}
	The signed distance between p_ACa and p_BCb.
Vector3< T >	nhat_BA_W
	A direction of fastest increasing distance.

Constructor & Destructor Documentation

SignedDistancePair() [1/4]

template<typename T>

SignedDistancePair ( const SignedDistancePair< T > & )

default

SignedDistancePair() [2/4]

template<typename T>

SignedDistancePair ( SignedDistancePair< T > && )

default

SignedDistancePair() [3/4]

template<typename T>

SignedDistancePair ( )

default

SignedDistancePair() [4/4]

template<typename T>

SignedDistancePair	(	GeometryId	a,
		GeometryId	b,
		const Vector3< T > &	p_ACa_in,
		const Vector3< T > &	p_BCb_in,
		const T &	dist,
		const Vector3< T > &	nhat_BA_W_in )

Constructor.

Parameters

a	The id of the first geometry (A).
b	The id of the second geometry (B).
p_ACa_in	The witness point on geometry A's surface, in A's frame.
p_BCb_in	The witness point on geometry B's surface, in B's frame.
dist	The signed distance between p_A and p_B.
nhat_BA_W_in	A direction of fastest increasing distance.

Precondition

nhat_BA_W_in is unit-length.

Member Function Documentation

operator=() [1/2]

template<typename T>

SignedDistancePair & operator= ( const SignedDistancePair< T > & )

default

operator=() [2/2]

template<typename T>

SignedDistancePair & operator= ( SignedDistancePair< T > && )

default

SwapAAndB()

template<typename T>

void SwapAAndB

(

)

Swaps the interpretation of geometries A and B.

Member Data Documentation

distance

template<typename T>

T distance {}

The signed distance between p_ACa and p_BCb.

id_A

template<typename T>

GeometryId id_A

The id of the first geometry in the pair.

id_B

template<typename T>

GeometryId id_B

The id of the second geometry in the pair.

nhat_BA_W

template<typename T>

Vector3<T> nhat_BA_W

A direction of fastest increasing distance.

p_ACa

template<typename T>

Vector3<T> p_ACa

The witness point on geometry A's surface, expressed in A's frame.

p_BCb

template<typename T>

Vector3<T> p_BCb

The witness point on geometry B's surface, expressed in B's frame.

---

The documentation for this struct was generated from the following file:

• drake/geometry/query_results/signed_distance_pair.h