libMesh::Plane Class Reference

#include <plane.h>

Inheritance diagram for libMesh::Plane:

[legend]

List of all members.

Public Member Functions
	Plane ()
	Plane (const Point &p, const Point &n)
	Plane (const Point &p0, const Point &p1, const Point &p2)
	Plane (const Plane &other_plane)
	~Plane ()
void	create_from_point_normal (const Point &p, const Point &n)
void	create_from_three_points (const Point &p0, const Point &p1, const Point &p2)
void	xy_plane (const Real zpos=0.)
void	xz_plane (const Real ypos=0.)
void	yz_plane (const Real xpos=0.)
bool	above_surface (const Point &p) const
bool	below_surface (const Point &p) const
bool	on_surface (const Point &p) const
Point	closest_point (const Point &p) const
Point	unit_normal (const Point &p) const
const Point &	get_planar_point () const
virtual Point	surface_coords (const Point &world_coords) const
virtual Point	world_coords (const Point &surf_coords) const
Private Member Functions
const Point &	normal () const
Private Attributes
Point	_point
Point	_normal

---

Detailed Description

This class defines a plane.

Author:

Benjamin S. Kirk, 2002

Definition at line 40 of file plane.h.

---

Constructor & Destructor Documentation

libMesh::Plane::Plane

(

)

Dummy Constructor.

Definition at line 32 of file plane.C.

{
}

libMesh::Plane::Plane	(	const Point &	p,
		const Point &	n
	)

Constructs a plane containing point p with normal n.

Definition at line 38 of file plane.C.

References create_from_point_normal().

{
  this->create_from_point_normal (p, n);
}

libMesh::Plane::Plane	(	const Point &	p0,
		const Point &	p1,
		const Point &	p2
	)

Constructs a plane containing the three points. The normal is determined in a counter-clockwise sense. See the create_from_three_points method for more details.

Definition at line 46 of file plane.C.

References create_from_three_points().

{
  this->create_from_three_points (p0, p1, p2);
}

libMesh::Plane::Plane

(

const Plane &

other_plane

)

Copy-constructor.

Definition at line 55 of file plane.C.

References _normal, _point, and create_from_point_normal().

                                      :
  Surface()
{
  this->create_from_point_normal(other_plane._point,
                                 other_plane._normal);
}

libMesh::Plane::~Plane

(

)

Destructor. Does nothing at the moment.

Definition at line 64 of file plane.C.

{
}

---

Member Function Documentation

bool libMesh::Plane::above_surface

(

const Point &

p

)

const [virtual]

Returns:

true if the point p is above the surface, false otherwise.

Implements libMesh::Surface.

Definition at line 127 of file plane.C.

References _point, normal(), and libMesh::Real.

Referenced by below_surface().

{
  // Create a vector from the surface to point p;
  const Point w = p - _point;

  // The point is above the surface if the projection
  // of that vector onto the normal is positive
  const Real proj = w*this->normal();

  if (proj > 0.)
    return true;

  return false;
}

bool libMesh::Plane::below_surface

(

const Point &

p

)

const [virtual]

Returns:

true if the point p is below the surface, false otherwise.

Implements libMesh::Surface.

Definition at line 144 of file plane.C.

References above_surface().

{
  return ( !this->above_surface (p) );
}

Point libMesh::Plane::closest_point

(

const Point &

p

)

const [virtual]

Returns:

the closest point on the surface to point p.

Implements libMesh::Surface.

Definition at line 169 of file plane.C.

References _point, and normal().

{
  // Create a vector from the surface to point p;
  const Point w = p - _point;

  // The closest point in the plane to point p
  // is in the negative normal direction
  // a distance w (dot) p.
  const Point cp = p - this->normal()*(w*this->normal());

  return cp;
}

void libMesh::Plane::create_from_point_normal	(	const Point &	p,
		const Point &	n
	)

Defines a plane containing point p with normal n.

Definition at line 70 of file plane.C.

References _normal, _point, and libMesh::TypeVector< T >::unit().

Referenced by Plane().

{
  _normal = n.unit();
  _point  = p;
}

void libMesh::Plane::create_from_three_points	(	const Point &	p0,
		const Point &	p1,
		const Point &	p2
	)

Defines a plane intersecting the three points p0, p1, and p2. The normal is constructed in a counter-clockwise sense, i.e. (p1-p0)x(p2-p0);

Definition at line 78 of file plane.C.

References _normal, _point, libMesh::TypeVector< T >::cross(), and libMesh::TypeVector< T >::unit().

Referenced by Plane().

{
  // Just use p0 for the point.
  _point = p0;

  const Point e0 = p1 - p0;
  const Point e1 = p2 - p0;
  const Point n  = e0.cross(e1);

  _normal = n.unit();
}

const Point & libMesh::Plane::get_planar_point

(

)

const

Returns:

a point on the plane useful for determining position

Definition at line 189 of file plane.C.

References _point.

{
  return _point;
}

const Point & libMesh::Plane::normal

(

)

const [inline, private]

Returns the normal for the plane.

Definition at line 158 of file plane.h.

References _normal.

Referenced by above_surface(), closest_point(), and on_surface().

{
  return _normal;
}

bool libMesh::Plane::on_surface

(

const Point &

p

)

const [virtual]

Returns:

true if the point p is on the surface, false otherwise. Note that the definition of on the surface really means "very close" to account for roundoff error.

Implements libMesh::Surface.

Definition at line 151 of file plane.C.

References _point, std::abs(), normal(), and libMesh::Real.

{
  // Create a vector from the surface to point p;
  const Point w = p - _point;

  // If the projection of that vector onto the
  // plane's normal is 0 then the point is in
  // the plane.
  const Real proj = w * this->normal();

  if (std::abs(proj) < 1.e-10)
    return true;

  return false;
}

Point libMesh::Surface::surface_coords

(

const Point &

world_coords

)

const [inline, virtual, inherited]

Returns:

the Point world_coords in the surface's coordinate system. world_coords is in the world coordinate system. This method is not purely virtual, because there may be surfaces that do not have an own coordinate system. These simply do not have to overload this method.

Reimplemented in libMesh::Sphere.

Definition at line 121 of file surface.h.

{
  Point p (from_world_coords);
  return p;
}

Point libMesh::Plane::unit_normal

(

const Point &

p

)

const [virtual]

Returns:

a unit vector normal to the surface at point p.

Implements libMesh::Surface.

Definition at line 184 of file plane.C.

References _normal.

{
  return _normal;
}

Point libMesh::Surface::world_coords

(

const Point &

surf_coords

)

const [inline, virtual, inherited]

Returns:

the world (cartesian) coordinates for the surface coordinates surf_coords. This method is not purely virtual, because there may be surfaces that do not have an own coordinate system. These simply do not have to overload this method.

Reimplemented in libMesh::Sphere.

Definition at line 130 of file surface.h.

{
  Point p (surf_coords);
  return p;
}

void libMesh::Plane::xy_plane

(

const Real

zpos = 0.

)

Creates an XY plane located at z=zpos,

Definition at line 94 of file plane.C.

References _normal, and _point.

{
  const Point p (0., 0., zpos);
  const Point n (0., 0., 1.);

  _point  = p;
  _normal = n;
}

void libMesh::Plane::xz_plane

(

const Real

ypos = 0.

)

Creates an XZ plane located at y=ypos,

Definition at line 105 of file plane.C.

References _normal, and _point.

{
  const Point p (0., ypos, 0.);
  const Point n (0., 1., 0.);

  _point  = p;
  _normal = n;
}

void libMesh::Plane::yz_plane

(

const Real

xpos = 0.

)

Creates an YZ plane located at x=xpos,

Definition at line 116 of file plane.C.

References _normal, and _point.

{
  const Point p (xpos, 0., 0.);
  const Point n (1., 0., 0.);

  _point  = p;
  _normal = n;
}

---

Member Data Documentation

Point libMesh::Plane::_normal [private]

Definition at line 150 of file plane.h.

Referenced by create_from_point_normal(), create_from_three_points(), normal(), Plane(), unit_normal(), xy_plane(), xz_plane(), and yz_plane().

Point libMesh::Plane::_point [private]

The plane is defined by a point and a normal.

Definition at line 149 of file plane.h.

Referenced by above_surface(), closest_point(), create_from_point_normal(), create_from_three_points(), get_planar_point(), on_surface(), Plane(), xy_plane(), xz_plane(), and yz_plane().

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

• plane.h
• plane.C