Package org.jlab.geom.component

Class PrismaticComponent

java.lang.Object

org.jlab.geom.abs.AbstractComponent

org.jlab.geom.component.PrismaticComponent

All Implemented Interfaces:

Component, Transformable, Showable

Direct Known Subclasses:

DriftChamberWire, RectangularComponent

public abstract class PrismaticComponent
extends AbstractComponent

This class provides a basic implementation of the Component interface where the component's volume is defined by two convex polygons such that the edges of each polygon are connected to form trapezoidal sides.

These volumes are similar to geometric-prisms except that the two polygons do not need to be congruent and do not need to be related by a simple translation. Instead the two base polygons may be incongruent and have arbitrary positions and orientations relative to one another. The only requirement is that the two polygons have the same number of points and must be convex. As a result, the side faces of the volume may be trapezoids rather than parallelograms. Another way to describe these volumes is as generalized polygonal-frustums where the two cutting planes need non be parallel. To my knowledge, there is no simple word for such a shape.

In this documentation, the words "polygon", "base", and "face" are used interchangeably.

In addition to fulfilling most of the requirements for the Component interface, PrismaticComponent provides additional geometry data via getDirection() and getLine(). The direction is a Vector3D pointing from the component's midpoint towards the readout end of the component (eg towards the PMT of a scintillator). The line is a Line3D running down the middle of the length of the component from the geometric center of the first base to the geometric center of the second base.

For more information see Component.

Developer's Note: This class could be further abstracted such that points in two arbitrary similar-shapes defined by points could be connected to form a volume. This abstracted class could then be subtyped into classes to handle convex polygonal prisms, concave polygonal prisms, and handle cylindrical segment volumes (volumes with two sectors as bases).

Author:

jnhankins

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PrismaticComponent(int componentId, List<Point3D> firstFace, List<Point3D> secondFace)	Initializes a PrismaticComponent from the two given polygonal faces with the given component id.

Method Summary

Modifier and Type	Method	Description
Vector3D	getDirection()	Returns a vector pointing from the midpoint of this component towards the readout end of the component (eg towards the PMT of a scintillator).
double	getLength()	Returns the length of this component.
Line3D	getLine()	Returns a line running down the middle of the length of the component such that the two end points of the line segment are at the geometric centers of the the two polygons defining this component's volume.
boolean	getVolumeIntersection(Line3D line, Point3D inIntersect, Point3D outIntersect)	Returns true if the given line segment intersect the volume-shape twice (one incoming intersection and one out going) and stores the incoming and outgoing intersection points are stored in the first and second Point3D objects given as arguments respectively.
protected void	onRotateX(double angle)	Classes extending AbstractComponent should implement onRotateX so that any additional geometric data they contain is rotated appropriately when AbstractComponent's rotateX method is invoke.
protected void	onRotateY(double angle)	Classes extending AbstractComponent should implement onRotateY so that any additional geometric data they contain is rotated appropriately when AbstractComponent's rotateY method is invoke.
protected void	onRotateZ(double angle)	Classes extending AbstractComponent should implement onRotateZ so that any additional geometric data they contain is rotated appropriately when AbstractComponent's rotateZ method is invoke.
protected void	onTranslateXYZ(double dx, double dy, double dz)	Classes extending AbstractComponent should implement onTranslateXYZ so that any additional geometric data they contain is translated appropriately when AbstractComponent's translateXYZ method is invoked.

Methods inherited from class org.jlab.geom.abs.AbstractComponent

addVolumeEdge, addVolumePoint, addVolumeTriangleFace, getComponentId, getMidpoint, getNumVolumeEdges, getNumVolumePoints, getVolumeCrossSection, getVolumeEdge, getVolumePoint, getVolumeShape, rotateX, rotateY, rotateZ, show, toString, translateXYZ

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.jlab.geom.base.Component

getType

Constructor Details

PrismaticComponent

protected PrismaticComponent(int componentId,
 List<Point3D> firstFace,
 List<Point3D> secondFace)

Initializes a PrismaticComponent from the two given polygonal faces with the given component id.

Parameters:

componentId - the id of the component

firstFace - the first polygonal base

secondFace - the second polygonal base

Throws:

IllegalArgumentException - if the number of points in the first and second polygonal bases differ

IllegalArgumentException - if the points given lists do not form convex polygons

IllegalArgumentException - if the points in the first polygon are wound counter-clockwise from the perspective of an outside observer

IllegalArgumentException - if the points in the second polygon are wound clockwise from the perspective of an outside observer

Method Details

getDirection

public Vector3D getDirection()

Returns a vector pointing from the midpoint of this component towards the readout end of the component (eg towards the PMT of a scintillator).

Returns:

the direction of the readout end

getLine

public Line3D getLine()

Returns a line running down the middle of the length of the component such that the two end points of the line segment are at the geometric centers of the the two polygons defining this component's volume. By convention, the origin point of the line lies at the geometric center of the first face and the end point of the line lies at the geometric center of the second face.

Note that getLength()=getLine().length().

Returns:

a line running down the middle of the length the component

See Also:

• getLength()

getLength

public double getLength()

Description copied from interface: Component

Returns the length of this component.

Returns:

the length

onTranslateXYZ

protected void onTranslateXYZ(double dx,
 double dy,
 double dz)

Description copied from class: AbstractComponent

Classes extending AbstractComponent should implement onTranslateXYZ so that any additional geometric data they contain is translated appropriately when AbstractComponent's translateXYZ method is invoked. This method is called at the end of AbstractComponent's translateXYZ method.

Overrides:

onTranslateXYZ in class AbstractComponent

Parameters:

dx - amount to translate along the x axis

dy - amount to translate along the y axis

dz - amount to translate along the z axis

See Also:

• Transformable.translateXYZ(double, double, double)

onRotateX

protected void onRotateX(double angle)

Description copied from class: AbstractComponent

Classes extending AbstractComponent should implement onRotateX so that any additional geometric data they contain is rotated appropriately when AbstractComponent's rotateX method is invoke. This method is called at the end of AbstractComponent's rotateX method.

Overrides:

onRotateX in class AbstractComponent

Parameters:

angle - rotation angle in radians

See Also:

• Transformable.rotateX(double)

onRotateY

protected void onRotateY(double angle)

Description copied from class: AbstractComponent

Classes extending AbstractComponent should implement onRotateY so that any additional geometric data they contain is rotated appropriately when AbstractComponent's rotateY method is invoke. This method is called at the end of AbstractComponent's rotateY method.

Overrides:

onRotateY in class AbstractComponent

Parameters:

angle - rotation angle in radians

See Also:

• Transformable.rotateY(double)

onRotateZ

protected void onRotateZ(double angle)

Description copied from class: AbstractComponent

Classes extending AbstractComponent should implement onRotateZ so that any additional geometric data they contain is rotated appropriately when AbstractComponent's rotateZ method is invoke. This method is called at the end of AbstractComponent's rotateZ method.

Overrides:

onRotateZ in class AbstractComponent

Parameters:

angle - rotation angle in radians

See Also:

• Transformable.rotateZ(double)

getVolumeIntersection

public boolean getVolumeIntersection(Line3D line,
 Point3D inIntersect,
 Point3D outIntersect)

Returns true if the given line segment intersect the volume-shape twice (one incoming intersection and one out going) and stores the incoming and outgoing intersection points are stored in the first and second Point3D objects given as arguments respectively.

The incoming intersection is defined such that the incoming intersection point is closer to the origin of the line than the outgoing intersection point.

Developer's Note: For optimization, this algorithm assumes that

1. the volume contains N*4-4 triangular faces
2. the faces form a closed bounding volume
3. neither end point of the line segment are inside the volume
4. pairs of faces from index 0 through N*2-1 (i.e. 1 and 2, 2 and 3, 3 and 4, etc.) are coplanar (the side trapezoids)
5. the faces from N*2 through N*3-3 are coplanar (the first base)
6. the faces from N*3-3 through N*4-5 are coplanar (the second base)

where N is the number of points in either polygonal base.

Parameters:

line - the line segment

inIntersect - the incoming intersection

outIntersect - the outgoing intersection

Returns:

true if two intersections are found