From: ouv Date: Wed, 13 Oct 2010 09:49:12 +0000 (+0000) Subject: Issue 0020947: EDF 1467 SMESH: Modify the formula to calculate Aspect Ratio on quadra... X-Git-Url: http://git.salome-platform.org/gitweb/?a=commitdiff_plain;h=f0f625f60982875e656a1ca2b80beb062695e8da;p=modules%2Fsmesh.git Issue 0020947: EDF 1467 SMESH: Modify the formula to calculate Aspect Ratio on quadrangles --- diff --git a/doc/salome/gui/SMESH/images/formula5.png b/doc/salome/gui/SMESH/images/formula5.png new file mode 100644 index 000000000..823ba068d Binary files /dev/null and b/doc/salome/gui/SMESH/images/formula5.png differ diff --git a/doc/salome/gui/SMESH/input/aspect_ratio.doc b/doc/salome/gui/SMESH/input/aspect_ratio.doc index 070d377cc..5e1f31673 100644 --- a/doc/salome/gui/SMESH/input/aspect_ratio.doc +++ b/doc/salome/gui/SMESH/input/aspect_ratio.doc @@ -13,10 +13,10 @@ nodes is calculated by the formula: \image html formula4.png -- The Aspect Ratio of a \b quadrangle 2D element consisting of - 4 nodes is the worst (i.e. the greatest) value from all triangles - which can be built taking three nodes of the quadrangle. There are - four triangles to consider: +- The Aspect Ratio of a \b quadrangle 2D element consisting of 4 +nodes is calculated by the formula: + +\image html formula5.png \image html image138.gif diff --git a/src/Controls/SMESH_Controls.cxx b/src/Controls/SMESH_Controls.cxx index 4b370e61b..8f18f6605 100644 --- a/src/Controls/SMESH_Controls.cxx +++ b/src/Controls/SMESH_Controls.cxx @@ -465,46 +465,92 @@ double AspectRatio::GetValue( const TSequenceOfXYZ& P ) return alfa * maxLen * half_perimeter / anArea; } else if( nbNodes == 4 ) { // quadrangle - // return aspect ratio of the worst triange which can be built + // Compute lengths of the sides + std::vector< double > aLen (4); + aLen[0] = getDistance( P(1), P(2) ); + aLen[1] = getDistance( P(2), P(3) ); + aLen[2] = getDistance( P(3), P(4) ); + aLen[3] = getDistance( P(4), P(1) ); + // Compute lengths of the diagonals + std::vector< double > aDia (2); + aDia[0] = getDistance( P(1), P(3) ); + aDia[1] = getDistance( P(2), P(4) ); + // Compute areas of all triangles which can be built // taking three nodes of the quadrangle - TSequenceOfXYZ triaPnts(3); - // triangle on nodes 1 3 2 - triaPnts(1) = P(1); - triaPnts(2) = P(3); - triaPnts(3) = P(2); - double ar = GetValue( triaPnts ); - // triangle on nodes 1 3 4 - triaPnts(3) = P(4); - ar = Max ( ar, GetValue( triaPnts )); - // triangle on nodes 1 2 4 - triaPnts(2) = P(2); - ar = Max ( ar, GetValue( triaPnts )); - // triangle on nodes 3 2 4 - triaPnts(1) = P(3); - ar = Max ( ar, GetValue( triaPnts )); - - return ar; + std::vector< double > anArea (4); + anArea[0] = getArea( P(1), P(2), P(3) ); + anArea[1] = getArea( P(1), P(2), P(4) ); + anArea[2] = getArea( P(1), P(3), P(4) ); + anArea[3] = getArea( P(2), P(3), P(4) ); + // Q = alpha * L * C1 / C2, where + // + // alpha = sqrt( 1/32 ) + // L = max( L1, L2, L3, L4, D1, D2 ) + // C1 = sqrt( ( L1^2 + L1^2 + L1^2 + L1^2 ) / 4 ) + // C2 = min( S1, S2, S3, S4 ) + // Li - lengths of the edges + // Di - lengths of the diagonals + // Si - areas of the triangles + const double alpha = sqrt( 1 / 32. ); + double L = Max( aLen[ 0 ], + Max( aLen[ 1 ], + Max( aLen[ 2 ], + Max( aLen[ 3 ], + Max( aDia[ 0 ], aDia[ 1 ] ) ) ) ) ); + double C1 = sqrt( ( aLen[0] * aLen[0] + + aLen[1] * aLen[1] + + aLen[2] * aLen[2] + + aLen[3] * aLen[3] ) / 4. ); + double C2 = Min( anArea[ 0 ], + Min( anArea[ 1 ], + Min( anArea[ 2 ], anArea[ 3 ] ) ) ); + if ( C2 <= Precision::Confusion() ) + return 0.; + return alpha * L * C1 / C2; } else if( nbNodes == 8 ){ // nbNodes==8 - quadratic quadrangle - // return aspect ratio of the worst triange which can be built + // Compute lengths of the sides + std::vector< double > aLen (4); + aLen[0] = getDistance( P(1), P(3) ); + aLen[1] = getDistance( P(3), P(5) ); + aLen[2] = getDistance( P(5), P(7) ); + aLen[3] = getDistance( P(7), P(1) ); + // Compute lengths of the diagonals + std::vector< double > aDia (2); + aDia[0] = getDistance( P(1), P(5) ); + aDia[1] = getDistance( P(3), P(7) ); + // Compute areas of all triangles which can be built // taking three nodes of the quadrangle - TSequenceOfXYZ triaPnts(3); - // triangle on nodes 1 3 2 - triaPnts(1) = P(1); - triaPnts(2) = P(5); - triaPnts(3) = P(3); - double ar = GetValue( triaPnts ); - // triangle on nodes 1 3 4 - triaPnts(3) = P(7); - ar = Max ( ar, GetValue( triaPnts )); - // triangle on nodes 1 2 4 - triaPnts(2) = P(3); - ar = Max ( ar, GetValue( triaPnts )); - // triangle on nodes 3 2 4 - triaPnts(1) = P(5); - ar = Max ( ar, GetValue( triaPnts )); - - return ar; + std::vector< double > anArea (4); + anArea[0] = getArea( P(1), P(3), P(5) ); + anArea[1] = getArea( P(1), P(3), P(7) ); + anArea[2] = getArea( P(1), P(5), P(7) ); + anArea[3] = getArea( P(3), P(5), P(7) ); + // Q = alpha * L * C1 / C2, where + // + // alpha = sqrt( 1/32 ) + // L = max( L1, L2, L3, L4, D1, D2 ) + // C1 = sqrt( ( L1^2 + L1^2 + L1^2 + L1^2 ) / 4 ) + // C2 = min( S1, S2, S3, S4 ) + // Li - lengths of the edges + // Di - lengths of the diagonals + // Si - areas of the triangles + const double alpha = sqrt( 1 / 32. ); + double L = Max( aLen[ 0 ], + Max( aLen[ 1 ], + Max( aLen[ 2 ], + Max( aLen[ 3 ], + Max( aDia[ 0 ], aDia[ 1 ] ) ) ) ) ); + double C1 = sqrt( ( aLen[0] * aLen[0] + + aLen[1] * aLen[1] + + aLen[2] * aLen[2] + + aLen[3] * aLen[3] ) / 4. ); + double C2 = Min( anArea[ 0 ], + Min( anArea[ 1 ], + Min( anArea[ 2 ], anArea[ 3 ] ) ) ); + if ( C2 <= Precision::Confusion() ) + return 0.; + return alpha * L * C1 / C2; } return 0; }