SurfaceTri3 Class Reference

Derived class for 3-node triangular surface elements (Tri3). More...

#include <SurfaceTri3.h>

Inheritance diagram for SurfaceTri3:

Public Member Functions
	SurfaceTri3 (const Elem *elem)
	Constructor.
bool	intersect (const LineSegment &line_segment) const override
	Check if a line segment intersects this geometry.
Ball	computeBoundingBall () const override
	Compute a bounding ball for this geometry.
const Point &	normal () const
	Getter for the normal vector.
bool	intersect (const LineSegment &l, libMesh::Point &intersect_p) const
	Check if a line segment intersects this triangle.
bool	intersect (const LineSegment &line_segment) const override
	Check if a line segment intersects this triangle, without returning the intersection point.
const Elem &	elem () const
	Getter for the underlying element.
unsigned int	expectedEmbeddingMeshDim () const
	Getter of expected embedding solving mesh dimension Because the surface element is a face of the embedding mesh, its dimension is one less than the dimension of the embedding mesh.
Real	getProjectedBoundingBoxDiagonal (const Point &normal_dir) const
	Compute the length of the element bounding-box diagonal projected onto a plane orthogonal to a given direction.

Private Attributes
libMesh::Point	_p0
libMesh::Point	_p1
libMesh::Point	_p2
const Elem *	_elem
	Pointer to the libMesh element representing this surface face.
const Point	_normal
	Unit normal vector of the surface element.

Detailed Description

Derived class for 3-node triangular surface elements (Tri3).

Definition at line 16 of file SurfaceTri3.h.

Constructor & Destructor Documentation

SurfaceTri3()

SurfaceTri3::SurfaceTri3 ( const Elem *  elem )

explicit

Constructor.

Definition at line 13 of file SurfaceTri3.C.

  : Triangle(elem->point(0), elem->point(1), elem->point(2)),
    SurfaceElement(elem, Triangle::normal())
{
  mooseAssert(elem->type() == TRI3, "Element must be of type TRI3");
}

Member Function Documentation

computeBoundingBall()

Ball SurfaceTri3::computeBoundingBall ( ) const

inlineoverridevirtual

Compute a bounding ball for this geometry.

Sphere in 3D, circle in 2D. The ball should fully contain the geometry.

Implements GeometryBase.

Definition at line 33 of file SurfaceTri3.h.

{ return Triangle::computeBoundingBall(); }

elem()

const Elem & SurfaceElement::elem ( ) const

inlineinherited

Getter for the underlying element.

Definition at line 40 of file SurfaceElement.h.

{ return *_elem; }

Referenced by SurfaceEdge2::SurfaceEdge2(), SurfaceElement::SurfaceElement(), and SurfaceTri3().

expectedEmbeddingMeshDim()

unsigned int SurfaceElement::expectedEmbeddingMeshDim ( ) const

inlineinherited

Getter of expected embedding solving mesh dimension Because the surface element is a face of the embedding mesh, its dimension is one less than the dimension of the embedding mesh.

Definition at line 54 of file SurfaceElement.h.

{ return _elem->dim() + 1; }

getProjectedBoundingBoxDiagonal()

Real SurfaceElement::getProjectedBoundingBoxDiagonal ( const Point &  normal_dir ) const

inherited

Compute the length of the element bounding-box diagonal projected onto a plane orthogonal to a given direction.

The projection plane is defined only by its normal direction; the specific location (offset) of the plane is irrelevant for this operation. Equivalently, this function removes the component of the bounding-box diagonal along the given normal direction and returns the norm of the remaining tangential component.

Parameters

normal_dir

A direction vector defining the plane normal.

Returns

The length of the longest diagonal of the projected rectangle.

Definition at line 24 of file SurfaceElement.C.

{
  const BoundingBox bbox = _elem->loose_bounding_box();
  const Point d = bbox.second - bbox.first; // (dx, dy, dz), each >= 0
 
  // The longest diagonal of the projected AABB (its shadow on the plane orthogonal to
  // normal_dir) is the search radius that must cover this element's projected footprint.
  // Projecting only the main diagonal (dx, dy, dz) underestimates it whenever that diagonal
  // is nearly parallel to normal_dir. The projected footprint diameter is the max projected
  // length over all four space diagonals (dx, +/-dy, +/-dz); their negatives have identical
  // projected length, so these four combinations are exhaustive.
  Real max_projected = 0.0;
  for (const Real sy : {1.0, -1.0})
    for (const Real sz : {1.0, -1.0})
    {
      const Point diag(d(0), sy * d(1), sz * d(2));
      const Point tangent_vec = diag - normal_dir * (diag * normal_dir);
      max_projected = std::max(max_projected, tangent_vec.norm());
    }
 
  return max_projected;
}

intersect() [1/3]

bool Triangle::intersect	(	const LineSegment &	l,
		libMesh::Point &	intersect_p
	)		const

Check if a line segment intersects this triangle.

Definition at line 37 of file Triangle.C.

{
  const auto & a = line_segment.start();
  const auto & b = line_segment.end();
 
  // (a) Build basic vectors and choose a robust tolerance
  const Point dir = b - a;
 
  const Point edge1 = _p1 - _p0;
  const Point edge2 = _p2 - _p0;
  constexpr Real eps = libMesh::TOLERANCE;
 
  // (b) Test for parallel or degenerate configuration
  const Point pvec = dir.cross(edge2);
  const Real det = edge1 * pvec;
  if (std::abs(det) < eps)
    return false; // ray nearly parallel to triangle
 
  const Real inv_det = 1.0 / det;
 
  // (c) Compute barycentric coordinate u and check 0 <= u <= 1
  const Point tvec = a - _p0;
  const Real u = (tvec * pvec) * inv_det;
  if (!MooseUtils::absoluteFuzzyGreaterEqual(u, 0.0, eps) ||
      !MooseUtils::absoluteFuzzyLessEqual(u, 1.0, eps))
    return false;
 
  // (d) Compute barycentric coordinate v and check 0 <= v and u + v <= 1
  const Point qvec = tvec.cross(edge1);
  const Real v = (dir * qvec) * inv_det;
  if (!MooseUtils::absoluteFuzzyGreaterEqual(v, 0.0, eps) ||
      !MooseUtils::absoluteFuzzyLessEqual(u + v, 1.0, eps))
    return false;
 
  // (e) Locate intersection along line segment (0 <= t <= 1 constrains to a--b)
  const Real t = (edge2 * qvec) * inv_det;
  if (!MooseUtils::absoluteFuzzyGreaterEqual(t, 0.0, eps) ||
      !MooseUtils::absoluteFuzzyLessEqual(t, 1.0, eps))
    return false;
 
  // (f) Intersection lies inside both the triangle and the segment
  intersect_p = a + dir * t;
  return true;
}

intersect() [2/3]

bool Triangle::intersect ( const LineSegment &  line_segment ) const

overridevirtual

Check if a line segment intersects this triangle, without returning the intersection point.

Implements GeometryBase.

Definition at line 42 of file Triangle.C.

{
  libMesh::Point p;
  return intersect(line_segment, p);
}

intersect() [3/3]

bool SurfaceTri3::intersect ( const LineSegment &  line_segment ) const

inlineoverridevirtual

Check if a line segment intersects this geometry.

Implements GeometryBase.

Definition at line 29 of file SurfaceTri3.h.

  {
    return Triangle::intersect(line_segment);
  }

normal()

const Point & SurfaceElement::normal ( ) const

inline

Getter for the normal vector.

Definition at line 43 of file SurfaceElement.h.

{ return _normal; }

Member Data Documentation

_elem

const Elem* SurfaceElement::_elem

privateinherited

Pointer to the libMesh element representing this surface face.

Derived classes access it through elem() rather than this field directly.

Definition at line 80 of file SurfaceElement.h.

Referenced by SurfaceElement::elem(), SurfaceElement::expectedEmbeddingMeshDim(), and SurfaceElement::getProjectedBoundingBoxDiagonal().

_normal

const Point SurfaceElement::_normal

privateinherited

Unit normal vector of the surface element.

Definition at line 82 of file SurfaceElement.h.

Referenced by SurfaceElement::normal(), and SurfaceElement::SurfaceElement().

_p0

libMesh::Point Triangle::_p0

privateinherited

Definition at line 50 of file Triangle.h.

Referenced by Triangle::computeBoundingBall(), and Triangle::normal().

_p1

libMesh::Point Triangle::_p1

privateinherited

Definition at line 50 of file Triangle.h.

Referenced by Triangle::computeBoundingBall(), and Triangle::normal().

_p2

libMesh::Point Triangle::_p2

privateinherited

Definition at line 50 of file Triangle.h.

Referenced by Triangle::computeBoundingBall(), and Triangle::normal().

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

• include/geometries/SurfaceTri3.h
• src/geometries/SurfaceTri3.C