fr.cnes.sirius.patrius.bodies.mesh

Class FacetBodyShape

java.lang.Object

fr.cnes.sirius.patrius.bodies.AbstractBodyShape

fr.cnes.sirius.patrius.bodies.mesh.FacetBodyShape

All Implemented Interfaces:

BodyShape, PVCoordinatesProvider, Serializable

Direct Known Subclasses:

StarConvexFacetBodyShape

public class FacetBodyShape
extends AbstractBodyShape

Facet body shape defined by a list of facets. A facet is a 3D triangle defined in the body frame.

This class offers an optimal storage under a Binary Space Partition Tree (BSP Tree). Each of the body facet (class Triangle) is linked to its neighbors. Each of the body vertex (class Vertex) is also linked to its neighboring triangles Triangle. Hence this class provides very efficient methods (O(log n)) for intersection computation, neighbors computation, etc.

This class implements the interface BodyShape:

• As a BodyShape, this class can be used in conjunction with EclipseDetector and SensorModel.

Since:

4.6

Author:

Emmanuel Bignon

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface fr.cnes.sirius.patrius.bodies.BodyShape

BodyShape.MarginType

Field Summary

Fields inherited from class fr.cnes.sirius.patrius.bodies.AbstractBodyShape

DEFAULT_EPSILON_SIGNAL_PROPAGATION, distanceEpsilon, lLHCoordinatesSystem

Fields inherited from interface fr.cnes.sirius.patrius.bodies.BodyShape

DEFAULT_DISTANCE_EPSILON, DIRECTION_FACTOR

Constructor Summary

Constructors

Constructor and Description
FacetBodyShape(String name, CelestialBodyFrame bodyFrame, MeshProvider meshLoader) Constructor.

Method Summary

Modifier and Type	Method and Description
FacetPoint	buildPoint(LLHCoordinatesSystem coordSystem, double latitude, double longitude, double height, String nameIn) Build a BodyPoint from LLH coordinates.
FacetPoint	buildPoint(Vector3D position, Frame frame, AbsoluteDate date, String nameIn) Build a BodyPoint from position in provided frame at provided date.
FacetPoint	buildPoint(Vector3D position, String nameIn) Build a BodyPoint from position in body frame.
FacetPoint[]	closestPointTo(Line line) This method computes the two points, on the line and on the body, that are the closest to each other.
FacetPoint[]	closestPointTo(Line line, Frame frame, AbsoluteDate date) This method computes the two points, on the line and on the body, that are the closest to each other.
FacetPoint	closestPointTo(Vector3D point) Computes the point on body surface that is the closest to provided point.
FacetPoint	closestPointTo(Vector3D point, Frame frame, AbsoluteDate date) Computes the point on body surface that is the closest to provided point.
FacetPoint	closestPointTo(Vector3D point, String nameIn) Computes the point on body surface that is the closest to provided point.
double	distanceTo(Line line, Frame frame, AbsoluteDate date) Computes the distance to a line.
double	getApparentRadius(PVCoordinatesProvider pvObserver, AbsoluteDate date, PVCoordinatesProvider occultedBody, AbstractSignalPropagationDetector.PropagationDelayType propagationDelayType) Compute the apparent radius (in meters) of the occulting body from the spacecraft (observer) position.
double	getEncompassingSphereRadius() Getter for the radius, in meters, of a sphere centered on the body frame origin and encompassing the shape.
FieldData	getFieldData(SpacecraftState state, IFieldOfView fieldOfView, Vector3D lineOfSight) Getter for the field data as FieldData for each state in provided list.
Intersection	getIntersection(Line line, Vector3D close, Frame frame, AbsoluteDate date) Getter for the intersection point of a line with the surface of the body.
FacetPoint	getIntersectionPoint(Line line, Vector3D close, Frame frame, AbsoluteDate date) Getter for the intersection point of a line with the surface of the body.
FacetPoint	getIntersectionPoint(Line line, Vector3D close, Frame frame, AbsoluteDate date, double altitude) Getter for the intersection point of a line with the surface of the body for a given altitude.
FacetPoint	getIntersectionPoint(Line line, Vector3D close, Frame frame, AbsoluteDate date, String nameIn) Getwter for the intersection point of a line with the surface of the body.
FacetPoint[]	getIntersectionPoints(Line line, Frame frame, AbsoluteDate date) Compute the intersection points with a line.
double	getMaxNorm() Getter for the distance from center to farthest vertex to center of body.
double	getMaxSlope() Getter for the maximum angle between the normal to a facet of the body and the vector from the origin to the centre of the facet.
MeshProvider	getMeshProvider() Getter for the mesh provider.
double	getMinNorm() Getter for the distance from center to closest vertex to center of body.
List<Triangle>	getNeighbors(BodyPoint point, double maxDistance) Getter for the neighbors of provided ellipsoid point whose center is closer than provided distance.
List<Triangle>	getNeighbors(BodyPoint point, int order) Getter for the neighbor triangles of provided body point which are closer or equal to provided order of "neighborhood".
List<Triangle>	getNeighbors(Triangle triangle, double maxDistance) Getter for the neighbors of provided triangle whose center is closer than provided distance of provided triangle center.
List<Triangle>	getNeighbors(Triangle triangle, int order) Getter for the neighbors of provided triangle whose distance in terms of triangle is closer or equal to provided order of "neighborhood".
List<Triangle>	getNeighbors(Vector3D pos, double maxDistance) Getter for the neighbors of provided cartesian point whose center is closer than provided distance.
List<Triangle>	getNeighbors(Vector3D pos, int order) Getter for the neighbor triangles of provided cartesian point which are closer or equal to provided order of "neighborhood".
List<Triangle>	getNeverEnlightenedTriangles(List<AbsoluteDate> dates, PVCoordinatesProvider sun) Getter for the list of triangles never enlightened by the Sun at provided dates.
List<Triangle>	getNeverVisibleTriangles(List<SpacecraftState> states, IFieldOfView fieldOfView) Getter for the list of triangles never visible from the satellite field of view during the whole ephemeris.
List<Triangle>	getOverPerpendicularSteepFacets() Find all facets from the mesh that break the convexity property of the facet body shape: the slope angle is over PI/2.
double	getThreshold() Getter for the threshold for apparent radius determination convergence.
Triangle[]	getTriangles() Getter for the mesh under a list of triangles.
List<Triangle>	getVisibleAndEnlightenedTriangles(List<SpacecraftState> states, PVCoordinatesProvider sun, IFieldOfView fieldOfView) Getter for the list of triangles enlightened (by the Sun) and visible at least once during the whole ephemeris from the satellite field of view.
boolean	isDefaultLLHCoordinatesSystem() Indicate if the current LLH coordinates system set for the body is the default one or not.
boolean	isInEclipse(AbsoluteDate date, Vector3D position, Frame frame, PVCoordinatesProvider sun) Returns true if provided position in provided frame at provided date in in eclipse or not.
boolean	isMasked(Triangle triangle, Vector3D pos) Returns true if the triangle is masked by another triangle as seen from the provided position.
boolean	isVisible(Triangle triangle, Vector3D pos, IFieldOfView fieldOfView, Transform t) Returns true if the triangle is visible from the field of view, i.e.: Is oriented toward the field of view All points of the triangle are in the field of view Triangle not masked by another facet
FacetBodyShape	resize(BodyShape.MarginType marginType, double marginValue) Resize the geometric body shape by a margin.
void	setMaxApparentRadiusSteps(int newLimit) Setter for the maximum number of steps in the while loop of BodyShape#getApparentRadius(PVCoordinatesProvider, AbsoluteDate, PVCoordinatesProvider, PropagationDelayType) method.
void	setThreshold(double threshold) Setter for the threshold for apparent radius determination convergence.

Methods inherited from class fr.cnes.sirius.patrius.bodies.AbstractBodyShape

getBodyFrame, getDistanceEpsilon, getEpsilonSignalPropagation, getLLHCoordinatesSystem, getName, getNativeFrame, getPVCoordinates, setDistanceEpsilon, setEpsilonSignalPropagation, setLLHCoordinatesSystem

Methods inherited from class java.lang.Object

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

Methods inherited from interface fr.cnes.sirius.patrius.bodies.BodyShape

buildRadialPointOnShapeSurface

Constructor Detail

FacetBodyShape

public FacetBodyShape(String name,
                      CelestialBodyFrame bodyFrame,
                      MeshProvider meshLoader)

Constructor.

Parameters:

name - body name

bodyFrame - frame in which celestial body coordinates are defined

meshLoader - mesh loader

Method Detail

getTriangles

public Triangle[] getTriangles()

Getter for the mesh under a list of triangles. The triangles are not sorted in any particular way.

Returns:

the mesh under a list of triangles

getIntersection

public Intersection getIntersection(Line line,
                                    Vector3D close,
                                    Frame frame,
                                    AbsoluteDate date)
                             throws PatriusException

Getter for the intersection point of a line with the surface of the body.

A line may have several intersection points with a closed surface (we consider the one point case as a degenerated two points case). The close parameter is used to select which of these points should be returned. The selected point is the one that is closest to the close point.

Parameters:

line - test line (may intersect the body or not)

close - point used for intersections selection expressed in the body frame

frame - frame in which line is expressed

date - date of the line in given frame

Returns:

or null if the line does not intersect the surface

Throws:

PatriusException - if line cannot be converted to body frame

getIntersectionPoint

public FacetPoint getIntersectionPoint(Line line,
                                       Vector3D close,
                                       Frame frame,
                                       AbsoluteDate date)
                                throws PatriusException

Getter for the intersection point of a line with the surface of the body.

A line may have several intersection points with a closed surface (we consider the one point case as a degenerated two points case). The close parameter is used to select which of these points should be returned. The selected point is the one that is closest to the close point.

The returned facet point is associated with one or several triangles following the closest point on shape position:

• 3 triangles or more if the closest point on shape corresponds to one shape vertex,
• 2 triangles if the closest point on shape belongs to one shape segment,
• 1 triangle in other cases.

Parameters:

line - test line (may intersect the body or not)

close - point used for intersections selection expressed in the body frame

frame - frame in which line is expressed

date - date of the line in given frame

Returns:

intersection point at altitude zero or null if the line does not intersect the surface

Throws:

PatriusException - if line cannot be converted to body frame

getIntersectionPoint

public FacetPoint getIntersectionPoint(Line line,
                                       Vector3D close,
                                       Frame frame,
                                       AbsoluteDate date,
                                       String nameIn)
                                throws PatriusException

Getwter for the intersection point of a line with the surface of the body.

A line may have several intersection points with a closed surface (we consider the one point case as a degenerated two points case). The close parameter is used to select which of these points should be returned. The selected point is the one that is closest to the close point.

The returned facet point is associated with one or several triangles following the closest point on shape position:

• 3 triangles or more if the closest point on shape corresponds to one shape vertex,
• 2 triangles if the closest point on shape belongs to one shape segment,
• 1 triangle in other cases.

Parameters:

line - test line (may intersect the body or not)

close - point used for intersections selection expressed in the body frame

frame - frame in which line is expressed

date - date of the line in given frame

nameIn - name of the point

Returns:

intersection point at altitude zero or null if the line does not intersect the surface

Throws:

PatriusException - if line cannot be converted to body frame

getIntersectionPoint

public FacetPoint getIntersectionPoint(Line line,
                                       Vector3D close,
                                       Frame frame,
                                       AbsoluteDate date,
                                       double altitude)
                                throws PatriusException

Getter for the intersection point of a line with the surface of the body for a given altitude.

A line may have several intersection points with a closed surface (we consider the one point case as a degenerated two points case). The close parameter is used to select which of these points should be returned. The selected point is the one that is closest to the close point.

Warning: this method returns getIntersectionPoint(Line, Vector3D, Frame, AbsoluteDate) if altitude is close to 0. An exception is thrown otherwise.

The returned facet point is associated with one or several triangles following the closest point on shape position:

• 3 triangles or more if the closest point on shape corresponds to one shape vertex,
• 2 triangles if the closest point on shape belongs to one shape segment,
• 1 triangle in other cases.

Parameters:

line - test line (may intersect the body or not)

close - point used for intersections selection expressed in the body frame

frame - frame in which line is expressed

date - date of the line in given frame

altitude - altitude of the intersection

Returns:

intersection point at provided altitude or null if the line does not intersect the surface

Throws:

PatriusException - if entered altitude is not close to 0 if line cannot be converted to body frame

getIntersectionPoints

public FacetPoint[] getIntersectionPoints(Line line,
                                          Frame frame,
                                          AbsoluteDate date)
                                   throws PatriusException

Compute the intersection points with a line.

Each facet point in the returned intersections array is associated with one single triangle (other possible belonging triangles not computed).

Parameters:

line - the line

frame - in which line is expressed

date - date of the line in given frame

Returns:

the intersection points if they exist. If no intersection is found, the dimension is zero

Throws:

PatriusException - if line cannot be converted to body frame

getOverPerpendicularSteepFacets

public List<Triangle> getOverPerpendicularSteepFacets()

Find all facets from the mesh that break the convexity property of the facet body shape: the slope angle is over PI/2. The slope angle is defined as the angle between the normal to the facet and the vector from the origin of the body shape to the centre of the facet. If the maxSlope is under PI/2, then the list shall be empty. See maxSlope.

Returns:

the list of facets violating the convexity property of the body shape

distanceTo

public double distanceTo(Line line,
                         Frame frame,
                         AbsoluteDate date)
                  throws PatriusException

Computes the distance to a line.

This method is exact and in O(n).

Parameters:

line - the line

frame - in which line is expressed

date - date of the line in given frame

Returns:

the shortest distance between the the line and the shape

Throws:

PatriusException - if line cannot be converted to body frame

getApparentRadius

public double getApparentRadius(PVCoordinatesProvider pvObserver,
                                AbsoluteDate date,
                                PVCoordinatesProvider occultedBody,
                                AbstractSignalPropagationDetector.PropagationDelayType propagationDelayType)
                         throws PatriusException

Compute the apparent radius (in meters) of the occulting body from the spacecraft (observer) position. Given a plane containing the spacecraft (observer) position, the center of the occulting body and the center of the occulted body, and given a line contained within this plane, passing by the spacecraft (observer) position and tangent to the mesh of the occulting body, the apparent radius corresponds to the length of the line starting from the center of the occulting body, perpendicular to the first given line and ending at the intersection of the two lines.

To compute the apparent radius (in meters), the algorithm iterates, until convergence, between the minimum and the maximum angles (and so radii too), given by the apparent angles (and so radii too) of this occulting body. Given the plane containing the observer, the occulted body and this occulting body, if the line lying on this plane and connecting the observer to the hypothetical tangential point of this occulting body actually intersects this occulting body, the search for the correct angle value by which this line shall be rotated (within the given plane) to be tangential to this occulting body will continue towards a larger angle, otherwise it will continue towards a smaller angle. Each time, this line is rotated by the current value of the angle and the value of the apparent radius is computed thanks to the current angle and the distance between the observer and this occulting body. Convergence is reached when the absolute value of the difference between the current value of the apparent radius and the previous one is smaller than a specified threshold (in meters).

Parameters:

pvObserver - the spacecraft (observer) position-velocity

date - the date at which the signal is received by the observer (reception date)

occultedBody - the body which is occulted to the spacecraft (observer) by the occulting body

propagationDelayType - propagation delay type

Returns:

the apparent radius (in meters) of the occulting body from the spacecraft (observer) position

Throws:

PatriusException - if the PVCoordinatesProvider computation fails

getNeighbors

public List<Triangle> getNeighbors(Triangle triangle,
                                   double maxDistance)

Getter for the neighbors of provided triangle whose center is closer than provided distance of provided triangle center.

Provided triangle is included in the list of neighbors.

Beware not to confuse this method with getNeighbors(Triangle, int)

Parameters:

triangle - a triangle

maxDistance - max distance

Returns:

the neighbors of provided triangle whose center is closer than provided distance of provided triangle center

getNeighbors

public List<Triangle> getNeighbors(Triangle triangle,
                                   int order)

Getter for the neighbors of provided triangle whose distance in terms of triangle is closer or equal to provided order of "neighborhood". For example:

• Order 0 returns provided triangle
• Order 1 returns provided triangle and the immediate neighbors of provided triangle
• Order 2 returns provided triangle, the immediate neighbors of provided triangle and also their own immediate neighbors

Beware not to confuse this method with getNeighbors(Triangle, double)

Parameters:

triangle - a triangle

order - order of "neighborhood"

Returns:

the neighbors of provided triangle whose distance in terms of triangle is closer or equal to provided order of "neighborhood"

getNeighbors

public List<Triangle> getNeighbors(BodyPoint point,
                                   double maxDistance)

Getter for the neighbors of provided ellipsoid point whose center is closer than provided distance.

Parameters:

point - a body point

maxDistance - max distance

Returns:

the neighbors of provided ellipsoid point whose center is closer than provided distance

getNeighbors

public List<Triangle> getNeighbors(BodyPoint point,
                                   int order)

Getter for the neighbor triangles of provided body point which are closer or equal to provided order of "neighborhood".
For example:

• Order 0 returns closest triangle
• Order 1 returns closest triangle and the immediate neighbors of closest triangle
• Order 2 returns closest triangle, the immediate neighbors of closest triangle and also their own immediate neighbors

Beware not to confuse this method with getNeighbors(BodyPoint, double)

Parameters:

point - a body point

order - order of "neighborhood"

Returns:

the neighbor triangles of provided body point which are closer or equal to provided order of "neighborhood"

getNeighbors

public List<Triangle> getNeighbors(Vector3D pos,
                                   double maxDistance)

Getter for the neighbors of provided cartesian point whose center is closer than provided distance.

Parameters:

pos - a point in body frame

maxDistance - max distance

Returns:

the neighbors of provided cartesian point whose center is closer than provided distance

getNeighbors

public List<Triangle> getNeighbors(Vector3D pos,
                                   int order)

Getter for the neighbor triangles of provided cartesian point which are closer or equal to provided order of "neighborhood". For example:

• Order 0 returns closest triangle
• Order 1 returns closest triangle and the immediate neighbors of closest triangle
• Order 2 returns closest triangle, the immediate neighbors of closest triangle and also their own immediate neighbors

Beware not to confuse this method with getNeighbors(Vector3D, double)

Parameters:

pos - a point in body frame

order - order of "neighborhood"

Returns:

the neighbor triangles of provided cartesian point which are closer or equal to provided order of "neighborhood"

getFieldData

public FieldData getFieldData(SpacecraftState state,
                              IFieldOfView fieldOfView,
                              Vector3D lineOfSight)
                       throws PatriusException

Getter for the field data as FieldData for each state in provided list.

Parameters:

state - spacecraft state

fieldOfView - sensor field of view

lineOfSight - optional parameter in order to indicate field of view main line of sight in spacecraft frame. If provided, this parameter may fasten algorithm by several order of magnitudes (O(log n) vs O(n)). Be careful, in this case, strongly not convex bodies may lead to missing some triangles.

Returns:

FieldData for corresponding state

Throws:

PatriusException - if state position could not be retrieved in body frame

isVisible

public boolean isVisible(Triangle triangle,
                         Vector3D pos,
                         IFieldOfView fieldOfView,
                         Transform t)
                  throws PatriusException

Returns true if the triangle is visible from the field of view, i.e.:

• Is oriented toward the field of view
• All points of the triangle are in the field of view
• Triangle not masked by another facet

Parameters:

triangle - a triangle

fieldOfView - field of view

pos - spacecraft position in body frame

t - transform from body frame to spacecraft frame

Returns:

true if the triangle is visible from the field of view

Throws:

PatriusException - if intersection computation failed

isMasked

public boolean isMasked(Triangle triangle,
                        Vector3D pos)
                 throws PatriusException

Returns true if the triangle is masked by another triangle as seen from the provided position. A triangle is masked if all its vertices are masked by at least another triangle.

Parameters:

triangle - a triangle

pos - spacecraft position in body frame

Returns:

true if the triangle is masked by another triangle as seen from the provided position

Throws:

PatriusException - if intersection computation failed

isInEclipse

public boolean isInEclipse(AbsoluteDate date,
                           Vector3D position,
                           Frame frame,
                           PVCoordinatesProvider sun)
                    throws PatriusException

Returns true if provided position in provided frame at provided date in in eclipse or not.

Computed eclipse status is exact and takes into account full body shape. This method cannot however be used in conjunction with EclipseDetector since they use a different framework.

This method uses the two following hypotheses: the propagation of the Sun light is instantaneous and the Sun is a point source. Please note that the apparent angle of the Sun as seen from the Earth is about 0.5 degrees, while the one seen from Mars is, to the nearest, roughly 0.38 degrees.

Parameters:

date - date

position - position

frame - frame in which position is expressed

sun - Sun body

Returns:

true if provided position in provided frame at provided date in in eclipse or not

Throws:

PatriusException - if failed to retrieve Sun position of intersection points with body

getNeverVisibleTriangles

public List<Triangle> getNeverVisibleTriangles(List<SpacecraftState> states,
                                               IFieldOfView fieldOfView)
                                        throws PatriusException

Getter for the list of triangles never visible from the satellite field of view during the whole ephemeris. A visible triangle must be properly oriented, in the field of view and not masked by any other triangle.

Parameters:

states - list of spacecraft states

fieldOfView - field of view

Returns:

list of Triangle never visible from the satellite field of view during the whole ephemeris

Throws:

PatriusException - if state position could not be retrieved in body frame

getNeverEnlightenedTriangles

public List<Triangle> getNeverEnlightenedTriangles(List<AbsoluteDate> dates,
                                                   PVCoordinatesProvider sun)
                                            throws PatriusException

Getter for the list of triangles never enlightened by the Sun at provided dates. An enlightened triangle must be properly oriented toward the Sun and not masked by any other triangle.

Parameters:

dates - list of dates

sun - Sun body

Returns:

list of Triangle never enlightened by the Sun

Throws:

PatriusException - if state position could not be retrieved in body frame

getVisibleAndEnlightenedTriangles

public List<Triangle> getVisibleAndEnlightenedTriangles(List<SpacecraftState> states,
                                                        PVCoordinatesProvider sun,
                                                        IFieldOfView fieldOfView)
                                                 throws PatriusException

Getter for the list of triangles enlightened (by the Sun) and visible at least once during the whole ephemeris from the satellite field of view. A visible triangle must be properly oriented, in the field of view and not masked by any other triangle.
An enlightened triangle must be properly oriented toward the Sun and not masked by any other triangle.

Parameters:

states - list of spacecraft states

sun - sun

fieldOfView - field of view

Returns:

list of Triangle enlightened and visible at least once from the satellite field of view

Throws:

PatriusException - if state position could not be retrieved in body frame

getMinNorm

public double getMinNorm()

Getter for the distance from center to closest vertex to center of body.

Returns:

the distance from center to closest vertex to center of body

getMaxNorm

public double getMaxNorm()

Getter for the distance from center to farthest vertex to center of body.

Returns:

the distance from center to farthest vertex to center of body

getThreshold

public double getThreshold()

Getter for the threshold for apparent radius determination convergence.

Returns:

the threshold for apparent radius determination convergence

getMeshProvider

public MeshProvider getMeshProvider()

Getter for the mesh provider.

Returns:

the mesh provider

getMaxSlope

public double getMaxSlope()

Getter for the maximum angle between the normal to a facet of the body and the vector from the origin to the centre of the facet.

Returns:

the maxSlope

setThreshold

public void setThreshold(double threshold)

Setter for the threshold for apparent radius determination convergence.

Parameters:

threshold - the threshold for apparent radius determination convergence to set

resize

public FacetBodyShape resize(BodyShape.MarginType marginType,
                             double marginValue)

Resize the geometric body shape by a margin.

Parameters:

marginType - margin type to be used

marginValue - margin value to be used (in meters if the margin type is DISTANCE)

Returns:

resized geometric body shape with the margin

Throws:

IllegalArgumentException - if the margin value is invalid

setMaxApparentRadiusSteps

public void setMaxApparentRadiusSteps(int newLimit)

Setter for the maximum number of steps in the while loop of BodyShape#getApparentRadius(PVCoordinatesProvider, AbsoluteDate, PVCoordinatesProvider, PropagationDelayType) method.

Parameters:

newLimit - new maximum number of steps for apparent radius computation

closestPointTo

public FacetPoint[] closestPointTo(Line line,
                                   Frame frame,
                                   AbsoluteDate date)
                            throws PatriusException

This method computes the two points, on the line and on the body, that are the closest to each other. The returned points are identical if the line intersects the shape: this point is the one with the lowest abscissa. The returned point with index 0 is the point on the Line, while the returned point with index 1 is the point on this.

Note: calculations take the line's minimum abscissa into account.

This method is exact and in O(n).

The returned facet points are associated with one or several triangles following the closest point on shape position:

• 3 triangles or more if the closest point on shape corresponds to one shape vertex,
• 2 triangles if the closest point on shape belongs to one shape segment,
• 1 triangle in other cases.

Parameters:

line - the original line for the shortest distance computation

frame - the line's frame

date - the current date

Returns:

an array of length 2 containing the point of the line (slot [0]) and the point of the shape (slot [1]) expressed as BodyPoint (depending on body shape)

Throws:

PatriusException - if line cannot be converted to body frame

closestPointTo

public FacetPoint[] closestPointTo(Line line)

This method computes the two points, on the line and on the body, that are the closest to each other. The returned points are identical if the line intersects the shape: this point is the one with the lowest abscissa. The returned point with index 0 is the point on the Line, while the returned point with index 1 is the point on this.

Note: calculations take the line's minimum abscissa into account.

In this method we consider that the line's frame is the body frame, and the date is the AbsoluteDate.J2000_EPOCH.

This method is exact and in O(n).

The returned facet points are associated with one or several triangles following the closest point on shape position:

• 3 triangles or more if the closest point on shape corresponds to one shape vertex,
• 2 triangles if the closest point on shape belongs to one shape segment,
• 1 triangle in other cases.

Parameters:

line - the original line for the shortest distance computation

Returns:

an array of length 2 containing the point of the line (slot [0]) and the point of the shape (slot [1]) expressed as BodyPoint (depending on body shape)

closestPointTo

public FacetPoint closestPointTo(Vector3D point,
                                 Frame frame,
                                 AbsoluteDate date)
                          throws PatriusException

Computes the point on body surface that is the closest to provided point.

The returned facet point is associated with one or several triangles following the closest point position on the shape:

• 3 triangles or more if the closest point corresponds to one shape vertex,
• 2 triangles if the closest point belongs to one shape segment,
• 1 triangle in other cases.

Note: If several points on the shape are at the exact same minimal distance with respect to entered point, the method arbitrarily returns the first one.

Parameters:

point - a point expressed in provided frame

frame - frame

date - date

Returns:

the closest point to the provided point on the body surface

Throws:

PatriusException - if computation failed

closestPointTo

public FacetPoint closestPointTo(Vector3D point)

Computes the point on body surface that is the closest to provided point.

The returned facet point is associated with one or several triangles following the closest point position on the shape:

• 3 triangles or more if the closest point corresponds to one shape vertex,
• 2 triangles if the closest point belongs to one shape segment,
• 1 triangle in other cases.

Note: If several points on the shape are at the exact same minimal distance with respect to entered point, the method arbitrarily returns the first one.

Parameters:

point - a point expressed in body frame

Returns:

the closest point to the provided point on the body surface

closestPointTo

public FacetPoint closestPointTo(Vector3D point,
                                 String nameIn)

Computes the point on body surface that is the closest to provided point.

The returned facet point is associated with one or several triangles following the closest point position on the shape:

• 3 triangles or more if the closest point corresponds to one shape vertex,
• 2 triangles if the closest point belongs to one shape segment,
• 1 triangle in other cases.

Note: If several points on the shape are at the exact same minimal distance with respect to entered point, the method arbitrarily returns the first one.

Parameters:

point - a point expressed in body frame

nameIn - name of the point

Returns:

the closest point to the provided point on the body surface

buildPoint

public FacetPoint buildPoint(LLHCoordinatesSystem coordSystem,
                             double latitude,
                             double longitude,
                             double height,
                             String nameIn)

Build a BodyPoint from LLH coordinates. Type of returned body point depends on body.

Parameters:

coordSystem - LLH coordinates system in which are expressed the entered lat/long/height

latitude - input latitude

longitude - input longitude

height - input height

nameIn - name of the point

Returns:

a body point

buildPoint

public FacetPoint buildPoint(Vector3D position,
                             String nameIn)

Build a BodyPoint from position in body frame. Type of returned body point depends on body.

Parameters:

position - position in body frame

nameIn - name of the point

Returns:

BodyPoint from position in body frame

buildPoint

public FacetPoint buildPoint(Vector3D position,
                             Frame frame,
                             AbsoluteDate date,
                             String nameIn)
                      throws PatriusException

Build a BodyPoint from position in provided frame at provided date. Type of returned body point depends on body.

Parameters:

position - position in provided frame at provided date

frame - frame

date - date

nameIn - name of the point

Returns:

BodyPoint from position in provided frame at provided date

Throws:

PatriusException - if failed to build point

getEncompassingSphereRadius

public double getEncompassingSphereRadius()

Getter for the radius, in meters, of a sphere centered on the body frame origin and encompassing the shape.

Returns:

the encompassing radius

isDefaultLLHCoordinatesSystem

public boolean isDefaultLLHCoordinatesSystem()

Indicate if the current LLH coordinates system set for the body is the default one or not.

Returns:

true if the current LLH coordinates system is the default one, false otherwise