jvx.geom
Class PwCurvature

java.lang.Object
  |
  +--jv.object.PsObject
        |
        +--jvx.geom.PwCurvature

All Implemented Interfaces:

java.lang.Cloneable, PsUpdateIf, java.io.Serializable

public class PwCurvature

extends PsObject

Compute various discrete curvature terms of a polyhedral surface.

Version:

24.06.98, 1.01 revised (kp) Moved from PgElementSet in separate class.
01.06.98, 1.00 created (kp)

Author:

Konrad Polthier

See Also:

PgElementSet, Serialized Form

Fields inherited from class jv.object.PsObject

HAS_CONFIG_PANEL, HAS_INFO_PANEL, HAS_MATERIAL_PANEL, HAS_TEXTURE_PANEL, INSPECTOR_INFO, INSPECTOR_INFO_EXT, IS_DELETED, IS_FIXED, IS_SELECTED, IS_USED, NUM_TAGS

Constructor Summary

PwCurvature()

Method Summary

static double	getGaussCurvature(PgElementSet geom, int aVertexInd) Get Gauss curvature at vertex with given index.
static double	getGaussCurvature(PgElementSet geom, PdVector gauss) Compute discrete Gauss curvature at all vertices, and return total interior Gauss curvature.
static boolean	getMeanCurvature(PgElementSet geom) Compute and assign vertex normals as mean curvature vectors.
static PdVector	getMeanCurvature(PgElementSet geom, PdVector mean) Compute the mean curvature at all vertices.
static PdVector[]	getMeanCurvature(PgElementSet geom, PdVector[] meanVec) Compute discrete mean curvature at all vertices.
static boolean	getPrincipalCurvature(PgElementSet geom) Compute vertex normals as mean curvature vectors and set enable showing of vertex normals.
static PdVector[][]	getPrincipalCurvature(PgElementSet geom, PdVector[][] vec) Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form.
static boolean	getPrincipalCurvatureAngle(PgElementSet geom) Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form.
static PdVector[][]	getPrincipalCurvatureAngle(PgElementSet geom, PdVector[][] vec) Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form.
static boolean	getPrincipalCurvatureArea(PgElementSet geom) Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form.
static PdVector[][]	getPrincipalCurvatureArea(PgElementSet geom, PdVector[][] vec) Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form.
static void	makeColorFromGaussCurvature(PgElementSet geom) Show discrete Gauss curvature at all vertices and elements.

Methods inherited from class jv.object.PsObject

addInspector, addUpdateListener, assureInspector, clearTag, clone, clone, clone, copy, getFather, getInfoPanel, getInspector, getName, getNumObjects, hasInspector, hasTag, hasUpdateListener, init, instanceOf, instanceOf, removeInspector, removeUpdateListener, setName, setParent, setTag, toString, update, updatePanels

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PwCurvature

public PwCurvature()

Method Detail

makeColorFromGaussCurvature

public static void makeColorFromGaussCurvature(PgElementSet geom)

Show discrete Gauss curvature at all vertices and elements. Method calls #getGaussCurvature(PgElementSet,PdVector).

getGaussCurvature

public static double getGaussCurvature(PgElementSet geom,
                                       int aVertexInd)

Get Gauss curvature at vertex with given index. HACK: Method is not implemented yet.

getGaussCurvature

public static double getGaussCurvature(PgElementSet geom,
                                       PdVector gauss)

Compute discrete Gauss curvature at all vertices, and return total interior Gauss curvature. If argument array is null or wrong size, it is created or its length is adjusted. Curvature is computed only for vertices which are referenced by elements. If a vertex is not reference, then its curvature value is 0. Curvature of boundary vertices is defined 0, therefore method requires a correct neighbour structure.

Note, polygonal faces with m>3 vertices are triangulated on the fly by cutting off the vertex with smallest vertex angle successively. This tries to ensure that the Gauss curvature is independent of the numbering of vertices inside an element, as it would depend on if we would use subtriangles {v[0],v[j],v[j+1]}.

If geometry has elements with more than three edges then we need the element normals for triangulating those elements. If the element normals do not exist in such a case, then we generate them using makeElementNormals().

Returns:

total Gauss curvature

getMeanCurvature

public static PdVector[] getMeanCurvature(PgElementSet geom,
                                          PdVector[] meanVec)

Compute discrete mean curvature at all vertices. If argument array is null or wrong size, it is created or its length is adjusted. Curvature is computed only for vertices which are referenced by elements. If a vertex is not reference, then its curvature value is 0. Curvature of boundary vertices is defined 0, therefore method requires correct neighbour structure.

Returns:

array of mean curvature vectors, one vector per vertex

getMeanCurvature

public static boolean getMeanCurvature(PgElementSet geom)

Compute and assign vertex normals as mean curvature vectors. Showing of vertex normals must be enabled elsewhere.

Returns:

true on success.

getMeanCurvature

public static PdVector getMeanCurvature(PgElementSet geom,
                                        PdVector mean)

Compute the mean curvature at all vertices.

Careful: If array 'mean' is too small then a new array with correct size is created, i.e. the array is not expanded.

Method requires existence of correct vertex normals to compute the sign. Mean curvature is negative of mean curvature vector has negative scalar product with vertex normal.

Returns:

vector with a scalar mean curvature value per vertex

getPrincipalCurvature

public static boolean getPrincipalCurvature(PgElementSet geom)

Compute vertex normals as mean curvature vectors and set enable showing of vertex normals.

getPrincipalCurvatureArea

public static boolean getPrincipalCurvatureArea(PgElementSet geom)

Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form. This method uses weighting of according to the area of adjacent elements.

getPrincipalCurvatureAngle

public static boolean getPrincipalCurvatureAngle(PgElementSet geom)

Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form. This method uses weighting of according to the Angle of adjacent elements.

getPrincipalCurvature

public static PdVector[][] getPrincipalCurvature(PgElementSet geom,
                                                 PdVector[][] vec)

Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form. This method does not use any weighting.

getPrincipalCurvatureArea

public static PdVector[][] getPrincipalCurvatureArea(PgElementSet geom,
                                                     PdVector[][] vec)

Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form. This method uses weighting of according to the area of adjacent elements.

getPrincipalCurvatureAngle

public static PdVector[][] getPrincipalCurvatureAngle(PgElementSet geom,
                                                      PdVector[][] vec)

Compute principal curvature directions and values as eigenvectors and eigenvalues from a quadratic form. This method uses weighting of according to the angle of adjacent elements.