SurfArea.cpp File Reference

#include "moab/Core.hpp"
#include "moab/Range.hpp"
#include "moab/CartVect.hpp"
#include <iostream>

Include dependency graph for SurfArea.cpp:

Go to the source code of this file.

Functions
double	compute_area (std::vector< EntityHandle > &)
int	main (int argc, char **argv)

Variables
Interface *	mb

Function Documentation

compute_area()

double compute_area

(

std::vector< EntityHandle > &

entities

)

Definition at line 95 of file SurfArea.cpp.

{
 
 ErrorCode rval = MB_SUCCESS;
 double area = 0.0;
 
 // loop thro' all the elements
 for( int i = 0; i < int( entities.size() ); i++ )
 {
 std::vector< EntityHandle > conn;
 EntityHandle handle = entities[i];
 
 // get the connectivity of this element
 rval = mb->get_connectivity( &handle, 1, conn );
 if( MB_SUCCESS != rval ) return -1.0;
 
 // break polygon into triangles and sum the area - Limitation: Convex polygon
 for( int j = 2; j <= int( conn.size() ); ++j )
 {
 
 EntityHandle vertices[3] = { conn[0], conn[j - 1], conn[j - 2] };
 CartVect coords[3];
 
 // get 3 coordinates forming the triangle
 rval = mb->get_coords( vertices, 3, coords[0].array() );
 if( MB_SUCCESS != rval ) return -1.0;
 
 CartVect edge0 = coords[1] - coords[0];
 CartVect edge1 = coords[2] - coords[0];
 
 // using MBCarVect overloaded operators and computing triangle area
 area += ( edge0 * edge1 ).length() / 2.0;
 }
 }
 // clear the entities, else old entities remain
 entities.clear();
 return area;
}

References entities, ErrorCode, moab::Interface::get_connectivity(), moab::Interface::get_coords(), length(), mb, and MB_SUCCESS.

Referenced by main().

main()

int main	(	int	argc,
		char **	argv
	)

Definition at line 22 of file SurfArea.cpp.

{
 if( 1 == argc )
 {
 std::cout << "Usage: " << argv[0] << " <filename>" << std::endl;
 return 0;
 }
 
 // declare variables
 Tag gtag, idtag;
 ErrorCode rval;
 const char* tag_geom = "GEOM_DIMENSION";
 const char* tag_gid = "GLOBAL_ID";
 Range sets;
 std::vector< EntityHandle > ents;
 
 // load a file
 mb = new Core();
 rval = mb->load_file( argv[1] );
 if( MB_SUCCESS != rval ) return 1;
 
 // get the tag handle for the tags
 rval = mb->tag_get_handle( tag_geom, 1, MB_TYPE_INTEGER, gtag );
 if( MB_SUCCESS != rval ) return 1;
 rval = mb->tag_get_handle( tag_gid, 1, MB_TYPE_INTEGER, idtag );
 if( MB_SUCCESS != rval ) return 1;
 
 // get all the sets with GEOM_DIMESION tag
 rval = mb->get_entities_by_type_and_tag( 0, MBENTITYSET, &gtag, NULL, 1, sets );
 if( MB_SUCCESS != rval ) return 1;
 
 // iterate over each set, getting entities
 Range::iterator set_it;
 
 // loop thru all the geometric entity sets
 for( set_it = sets.begin(); set_it != sets.end(); ++set_it )
 {
 
 EntityHandle this_set = *set_it;
 
 // get the id for this set
 int set_id;
 rval = mb->tag_get_data( gtag, &this_set, 1, &set_id );
 if( MB_SUCCESS != rval ) return 1;
 
 // check if it is a surface entities (GEOM_DIMENSION 2) then compute area
 if( set_id == 2 )
 {
 
 // area of a surface
 double total_area = 0.0;
 
 // get the global id of this surface
 int gid = 0;
 rval = mb->tag_get_data( idtag, &this_set, 1, &gid );
 if( MB_SUCCESS != rval ) return 1;
 
 // get all entities with dimension 2 in ents
 rval = mb->get_entities_by_dimension( this_set, 2, ents );
 if( MB_SUCCESS != rval ) return 1;
 
 // compute the area
 total_area = compute_area( ents );
 
 ents.clear();
 
 std::cout << "Total area of meshes in surface " << gid << " = " << total_area << std::endl;
 }
 }
}

References moab::Range::begin(), compute_area(), moab::Range::end(), ErrorCode, moab::Interface::get_entities_by_dimension(), moab::Interface::get_entities_by_type_and_tag(), moab::Interface::load_file(), mb, MB_SUCCESS, MB_TYPE_INTEGER, MBENTITYSET, moab::Interface::tag_get_data(), and moab::Interface::tag_get_handle().

Variable Documentation

mb

Interface* mb

Definition at line 20 of file SurfArea.cpp.

Referenced by compute_area(), and main().