snappyHexMeshConfig: use implicitFeatures by default

and make '-explicitFeatures' the option to use explicitFeatures. When implicitFeatures
is used, a surfaceFeaturesDict file is not written out to the system directory

applications/utilities/preProcessing/snappyHexMeshConfig/snappyHexMeshConfig.C

@@ -75,20 +75,20 @@ Description
     oriented along the z-axis along x = y = 0.
 
     The snappyHexMesh configuration is generated automatically, applying a set
-    of defaults to the main configuration parameters. By default, explicit
+    of defaults to the main configuration parameters. By default, implicit
-    feature capturing is configured, for which a surfaceFeaturesDict file is
+    feature capturing is configured.  Explicit feature capturing can
-    written for the user to generate the features files with the
+    alternatively be selected with the '-explicitFeatures' option, when an
-    surfaceFeatures utility. Implicit feature capturing can alternatively be
+    additional surfaceFeaturesDict file is written for the user to generate the
-    selected with the '-implicitFeatures' option. Refinement levels can be
+    features files with the surfaceFeatures utility.  Refinement levels can be
     controlled with a range of options including: '-refinementLevel' for the
     baseline refinement level; '-refinementSurfaces' for levels on specific
     surfaces; '-refinementRegions' for levels inside specific surfaces;
-    '-refinementBoxes' for quick, box-shaped refinement regions specified by
+    '-refinementBoxes' for quick, box-shaped refinement regions specified by min
-    min and max bounds; '-refinementDists' for distance-based refinement; and
+    and max bounds; '-refinementDists' for distance-based refinement; and
     '-nCellsBetweenLevels' to control the transition between refinement
     levels. A '-layers' option specifies additional layers of cells at wall
-    boundaries. The insidePoint parameter is set to '(0 0 0)' by default but
+    boundaries. The insidePoint parameter is set to '(0 0 0)' by default but can
-    can be overridden using the '-insidePoint' option.
+    be overridden using the '-insidePoint' option.
 
 Usage
     \b snappyHexMeshConfig [OPTIONS]
@@ -134,8 +134,8 @@ Usage
       - \par -clearBoundary,
         Do not set default patch entries, i.e. xMin, xMax, yMin, etc...
 
-      - \par -implicitFeatures,
+      - \par -explicitFeatures,
-        Use implicit feature capturing
+        Use explicit feature capturing, default is implicit
 
       - \par -layers \<int\>
         Specify <int> surface layers at wall boundaries, default 0
@@ -308,8 +308,8 @@ int main(int argc, char *argv[])
 
     argList::addBoolOption
     (
-        "implicitFeatures",
+        "explicitFeatures",
-        "use implicit feature capturing"
+        "use explicit feature capturing"
     );
 
     argList::addOption
@@ -569,7 +569,7 @@ int main(int argc, char *argv[])
         );
     }
 
-    const bool implicitFeatures(args.optionFound("implicitFeatures"));
+    const bool explicitFeatures(args.optionFound("explicitFeatures"));
 
     const label layers(args.optionLookupOrDefault<label>("layers", 0));
 
@@ -583,6 +583,8 @@ int main(int argc, char *argv[])
         args.optionLookupOrDefault<label>("nCellsBetweenLevels", 3)
     );
 
+    if (explicitFeatures)
+    {
         surfaceFeaturesConfiguration surfaceFeaturesConfig
         (
             "surfaceFeaturesDict",
@@ -592,6 +594,7 @@ int main(int argc, char *argv[])
         );
 
         surfaceFeaturesConfig.write();
+    }
 
     snappyHexMeshConfiguration snappyConfig
     (
@@ -604,7 +607,7 @@ int main(int argc, char *argv[])
         refinementRegions,
         refinementBoxes,
         refinementDists,
-        implicitFeatures,
+        explicitFeatures,
         layers,
         insidePoint,
         nCellsBetweenLevels

applications/utilities/preProcessing/snappyHexMeshConfig/snappyHexMeshConfiguration.C

@@ -133,7 +133,7 @@ void Foam::snappyHexMeshConfiguration::writeFeatures()
 {
     beginList(os_, "features");
 
-    if (!implicitFeatures_)
+    if (explicitFeatures_)
     {
         forAll(surfaces_, i)
         {
@@ -422,9 +422,9 @@ void Foam::snappyHexMeshConfiguration::writeSnapControls()
     beginDict(os_, "snapControls");
 
     os_ << indent << "explicitFeatureSnap    "
-        << (implicitFeatures_ ? "off" : "on") << ";" << endl;
+        << (explicitFeatures_ ? "on" : "off") << ";" << endl;
     os_ << indent << "implicitFeatureSnap    "
-        << (implicitFeatures_ ? "on" : "off") << ";" << endl;
+        << (explicitFeatures_ ? "off" : "on") << ";" << endl;
 
     endDict(os_);
 }
@@ -497,7 +497,7 @@ Foam::snappyHexMeshConfiguration::snappyHexMeshConfiguration
     const List<Tuple2<word, label>>& refinementRegions,
     const List<Tuple3<vector, vector, label>>& refinementBoxes,
     const List<Tuple3<word, scalar, label>>& refinementDists,
-    const bool implicitFeatures,
+    const bool explicitFeatures,
     const label layers,
     const point& insidePoint,
     const label nCellsBetweenLevels
@@ -510,7 +510,7 @@ Foam::snappyHexMeshConfiguration::snappyHexMeshConfiguration
     refinementRegions_(refinementRegions),
     refinementBoxes_(refinementBoxes),
     refinementDists_(refinementDists),
-    implicitFeatures_(implicitFeatures),
+    explicitFeatures_(explicitFeatures),
     layers_(layers),
     insidePoint_(insidePoint),
     nCellsBetweenLevels_(nCellsBetweenLevels)

applications/utilities/preProcessing/snappyHexMeshConfig/snappyHexMeshConfiguration.H

@@ -80,8 +80,8 @@ class snappyHexMeshConfiguration
         //- Refinement distances with level of refinement
         const List<Tuple3<word, scalar, label>>& refinementDists_;
 
-        //- Using implicit feature capturing?
+        //- Using explicit feature capturing?
-        const bool implicitFeatures_;
+        const bool explicitFeatures_;
 
         //- Number of layers at wall patches, default 0
         const label layers_;
@@ -173,7 +173,7 @@ public:
             const List<Tuple2<word, label>>& refinementRegions,
             const List<Tuple3<vector, vector, label>>& refinementBoxes,
             const List<Tuple3<word, scalar, label>>& refinementDists,
-            const bool implicitFeatures,
+            const bool explicitFeatures,
             const label layers,
             const point& insidePoint,
             const label nCellsBetweenLevels