only exclude boundary nodes of the "OpenBoundary" physical group if it's a curve (fixes #732)

Plugin/Crack.cpp

@@ -154,9 +154,11 @@ PView *GMSH_CrackPlugin::execute(PView *view)
       bndVertices.insert(it->data.begin(), it->data.end());
   }
 
-  // compute the boundary nodes (if any) of the "OpenBoundary" physical group
+  // compute the boundary nodes (if any) of the "OpenBoundary" physical group if
+  // it's a curve
   std::set<MVertex *> bndVerticesFromOpenBoundary;
   for(std::size_t i = 0; i < openEntities.size(); i++) {
+    if(openEntities[i]->dim() < 1) continue;
     for(std::size_t j = 0; j < openEntities[i]->getNumMeshElements(); j++) {
       MElement *e = openEntities[i]->getMeshElement(j);
       for(std::size_t k = 0; k < e->getNumVertices(); k++) {

benchmarks/2d/compound_with_physicals.geo

+//Mesh.CharacteristicLengthFromPoints = 0;
+lc=20;
+Point(1) = {1.8689e-35,3.99916e-33,0,lc};
+Point(2) = {8.33333,9.32267e-32,0,lc};
+Point(3) = {16.6667,7.58404e-33,0,lc};
+Point(4) = {25.0,-9.38607e-36,0,lc};
+Point(5) = {6.903e-33,5.34874,0,lc};
+Point(6) = {9.4089,10.8391,0,lc};
+Point(7) = {16.7265,10.0288,0,lc};
+Point(8) = {25.0479,9.96269,0,lc};
+Line(1)={1,2};
+Line(2)={2,6};
+Line(3)={5,6};
+Line(4)={1,5};
+Line(5)={2,3};
+Line(6)={3,7};
+Line(7)={6,7};
+Line(8)={3,4};
+Line(9)={4,8};
+Line(10)={7,8};
+Curve Loop(1)={1,2,-3,-4};
+Plane Surface(1)={1};
+Curve Loop(2)={5,6,-7,-2};
+Plane Surface(2)={2};
+Curve Loop(3)={8,9,-10,-6};
+Plane Surface(3)={3};
+
+Compound Surface{1,2,3};
+Physical Surface("setWPsurf")={1,2,3};
+
+Compound Curve{3,7,10};
+Physical Curve("setWPtop")={3,7,10};
+Compound Curve{1,5,8};
+Physical Curve("setWPbot")={1,5,8};
+Compound Curve{4};
+Physical Curve("setWPleft")={4};
+Compound Curve{9};
+Physical Curve("setWPright")={9};
+
+// the physicals will will work as well even if we don't reclassify on the
+//original surfaces:
+
+// Mesh.CompoundClassify = 0;