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0033828: Modeling Algorithms - GCPnts_QuasiUniformDeflection returns very different results under small change in deflection

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jfa 2024-09-17 17:51:36 +01:00 committed by dpasukhi
parent d8a26498d2
commit b0922ff9a1
2 changed files with 66 additions and 5 deletions
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36
src/GCPnts/GCPnts_QuasiUniformDeflection.cxx
View File

@ -103,29 +103,55 @@ static void QuasiFleche (const TheCurve& theC,
aVdelta = theVfin;
}
// square length of chord
const Standard_Real aNorme = gp_Vec (thePdeb, aPdelta).SquareMagnitude();
Standard_Real aFleche = 0.0;
Standard_Boolean isFlecheOk = Standard_False;
if (aNorme > theEps)
if (aNorme > theEps && aNorme > 16. * theDeflection2)
{
// Evaluation de la fleche par interpolation . Voir IntWalk_IWalking_5.gxx
Standard_Real N1 = theVdeb.SquareMagnitude();
Standard_Real N2 = aVdelta.SquareMagnitude();
if (N1 > theEps && N2 > theEps)
{
// square distance between ends of two normalized vectors [0; 4]
Standard_Real aNormediff = (theVdeb.Normalized().XYZ() - aVdelta.Normalized().XYZ()).SquareModulus();
if (aNormediff > theEps)
{
aFleche = aNormediff * aNorme / 64.0;
// So, fleche <= (aNorme / 16), independently of Vdeb and Vdelta.
// And if (aNorme / 16) < theDeflection2, this approach gives
// fleche < theDeflection2 independently of real curve.
// That is why we exclude case aNorme < (16. * theDeflection2)
isFlecheOk = Standard_True;
}
}
}
if (!isFlecheOk)
gp_Pnt aPmid ((thePdeb.XYZ() + aPdelta.XYZ()) * 0.5);
gp_Pnt aPverif (Value (theC, theUdeb + aUdelta * 0.5));
Standard_Real aFlecheMidMid = aPmid.SquareDistance (aPverif);
if (isFlecheOk)
{
gp_Pnt aPmid ((thePdeb.XYZ() + aPdelta.XYZ()) * 0.5);
gp_Pnt aPverif (Value (theC, theUdeb + aUdelta * 0.5));
aFleche = aPmid.SquareDistance (aPverif);
// Algorithm, evaluating "fleche" by interpolation,
// can give false-positive result.
// So we check also distance between Pmid and Pverif (aFlecheMidMid).
// But aFlecheMidMid gives worse result in case of non-uniform parameterisation.
// Maximum aFlecheMidMid, that seems reasonable, is (chord/2)^2 + theDeflection2
// .---------------.Pverif .
// | | | Deflection
// ._______. ______. .
// Pdeb Pmid Pdelta
if (aFlecheMidMid > aNorme/4. + theDeflection2)
//if (aFlecheMidMid > aNorme/4.)
{
aFleche = aFlecheMidMid;
}
}
else
{
aFleche = aFlecheMidMid;
}
if (aFleche < theDeflection2)

35
tests/bugs/moddata_3/bug33828 Normal file
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@ -0,0 +1,35 @@
puts "==========================================================="
puts "0033828: Modeling Data - GCPnts_QuasiUniformDeflection"
puts "returns very different results under small change in deflection"
puts "==========================================================="
proc check_crvpoints {cc deflection nb_expected} {
upvar ${cc} ${cc}
set str1 "Nb points +: +(\[-0-9.+eE\]+)\n"
set str2 "Max defl: +(\[-0-9.+eE\]+) +(\[-0-9.+eE\]+) +(\[-0-9.+eE\]+) +(\[-0-9.+eE\]+)"
set info [crvpoints r ${cc} ${deflection}]
regexp "${str1}${str2}" ${info} full Nb dmax ufmax ulmax i
if { ${Nb} != ${nb_expected} } {
puts "Error : bad value of Nb points = ${Nb}, expected ${nb_expected}"
}
if { ${dmax} > ${deflection} } {
puts "Error : bad value of maximum deflection = ${dmax}, expected < ${deflection}"
}
}
bsplinecurve cu 3 7 0 4 0.17 2 0.33 2 0.5 2 0.67 2 0.83 2 1 4 0.163 0.233 0 1 0.158 0.204 0 1 0.139 0.180 0 1 0.086 0.159 0 1 0.055 0.163 0 1 0.009 0.196 0 1 -0.004 0.225 0 1 0.002 0.281 0 1 0.019 0.307 0 1 0.070 0.332 0 1 0.101 0.331 0 1 0.149 0.301 0 1 0.164 0.274 0 1 0.163 0.246 0 1
check_crvpoints cu .5 2
check_crvpoints cu .1 3
check_crvpoints cu .05 5
check_crvpoints cu .025 5
check_crvpoints cu .007 9
check_crvpoints cu .005 17
check_crvpoints cu .0005 33
check_crvpoints cu .0003 65
check_crvpoints cu .0002 65
check_crvpoints cu .0001 73