Vega FEM Library (v1.1) User's Manual - University of Southern ...

Returns a pointer to the specified type of object, given its index in the list of that type of object in the
VolumetricMesh.
void setMaterial(int i, Material & material)
Sets the material at index i in the array of materials to material, and copies these material properties to
each mesh element whose containing region lists index i as the material which defines its material properties.
virtual double getElementVolume(int el) = 0
Implementations return the volume of the element at index el.
virtual bool containsVertex(int element, Vec3d pos) = 0
Returns whether the element at index i contains the vector pos.
int getClosestElement(Vec3d pos)
int getClosestVertex(Vec3d pos)
int getContainingElement(Vec3d pos)
Returns the index of the nearest element, nearest vertex, or containing element of pos in the undeformed
mesh. For the third function, -1 is returned if no containing element is found.
void exportMeshGeometry(int * numVertices, double ** vertices,
int * numElements, int * numElementVertices, int ** elements)
Exports the geometric information of the mesh to memory arrays. The number of vertices, number
of elements, and number of vertices per element are written to *numVertices, *numElements, and
*numElementVertices. Array *vertices is set to point to a newly-allocated (malloc) array of the coordinates
of all the vectors, and *elements is set to point to a newly-allocated (malloc) array of the indices of
the vertices constituting each mesh element.
int generateInterpolationWeights(int numTargetLocations,
double * targetLocations, int ** vertices, double ** weights,
double zeroThreshold = -1.0, std::vector * closestElementList = NULL,
int verbose=0)
Generates interpolation information for embedding a (typically higher-resolution) rendering mesh within
a deformable volumetric mesh. Given numTargetLocations points (rendering mesh vertices), with coordinates
specified in the array targetLocations, the function determines which mesh element is closest to
or contains each point. It then expresses each point’s position as a weighted average of the coordinates
of that element’s vertices, such that the weights sum to one (standard tet barycentric coordinates). Note
that weights may be negative if the point is outside the volumetric mesh. Output arrays *vertices and
*weights are allocated (malloc) inside the function. For each target location, the *vertices array gives the
integer indices of VolumetricMesh vertices of the mesh element containing the target. The array *weights
gives the barycentric weights. The length of both arrays is numElementVertices · numTargetLocations. If
zeroThreshold > 0, then the points that are further than zeroThreshold away from any volumetric mesh
vertex, are assigned weights of 0. If closestElementList is not NULL, the closest elements will be returned
in the vector closestElementList. The function returns the number of target points which do not lie inside
any element.
static int loadInterpolationWeights(char * filename,
int numTargetLocations, int numElementVertices,
int ** vertices, double ** weights)
static int saveInterpolationWeights(char * filename,
int numTargetLocations, int numElementVertices,
int * vertices, double * weights)
Reads or writes the arrays vertices and weights of interpolation information from or to filename.
Returns 0 iff successful.
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