ENH: surfaceSubset: add select-by-plane

applications/utilities/surface/surfaceSubset/surfaceSubset.C

@@ -42,6 +42,7 @@ Description
 #include "treeDataTriSurface.H"
 #include "Random.H"
 #include "volumeType.H"
+#include "plane.H"
 
 using namespace Foam;
 
@@ -277,6 +278,31 @@ int main(int argc, char *argv[])
     }
 
 
+    if (meshSubsetDict.found("plane"))
+    {
+        const dictionary& planeDict = meshSubsetDict.subDict("plane");
+
+        const plane pl(planeDict);
+        const scalar distance(readScalar(planeDict.lookup("distance")));
+        const scalar cosAngle(readScalar(planeDict.lookup("cosAngle")));
+
+        // Select all triangles that are close to the plane and
+        // whose normal aligns with the plane as well.
+
+        forAll(surf1.faceCentres(), faceI)
+        {
+            const point& fc = surf1.faceCentres()[faceI];
+            const point& nf = surf1.faceNormals()[faceI];
+
+            if (pl.distance(fc) < distance && mag(pl.normal() & nf) > cosAngle)
+            {
+                facesToSubset[faceI] = true;
+            }
+        }
+    }
+
+
+
     //
     // pick up specified "faces"
     //

applications/utilities/surface/surfaceSubset/surfaceSubsetDict

@@ -38,6 +38,27 @@ surface
     outside     yes;
 }
 
+// Select triangles on plane
+plane
+{
+    planeType embeddedPoints;
+    embeddedPointsDict
+    {
+        //point1 (-937.259845440205 160.865349115986 240.738791238078);
+        //point2 (-934.767379895778 9.63875523747379 14.412359671298);
+        //point3 (44.4744688899417 121.852927962709 182.352485273106);
+        point1 (-957.895294591874 242.865936478961 162.286611511875);
+        point2 (-961.43140327772 4.53895551562943 3.04159982093444);
+        point3 (91.2414146173805 72.1504381996692 48.2181961945329);
+    }
+
+    // Distance from plane
+    distance 0.1;
+    // Normal difference to plane
+    cosAngle 0.99;
+}
+
+
 // Extend selection with edge neighbours
 addFaceNeighbours no;