CONFIG: change default distanceSurface algorithm from 'cell' to 'topo'

- yields cleaner surfaces with few cuts.

  Can use isoMethod keyword to select cell/point/topo if they prove
  better for any particular case.

CONFIG: change default cuttingPlane algorithm from 'cell' to 'topo'

src/sampling/sampledSurface/distanceSurface/sampledDistanceSurface.H

@@ -50,7 +50,7 @@ Usage
         type     | distanceSurface                          | yes |
         distance | Distance from surface                    | yes |
         signed   | Use sign when distance is positive       | partly |
-        isoMethod | Iso-algorithm (cell/topo/point)         | no  | cell
+        isoMethod | Iso-algorithm (cell/topo/point)         | no  | topo
         regularise | Point snapping for iso-surface         | no  | true
         average  | Cell values from averaged point values   | no  | false
         bounds   | Limit with bounding box                  | no  |

src/sampling/sampledSurface/sampledCuttingPlane/sampledCuttingPlane.C

@@ -366,7 +366,7 @@ Foam::sampledCuttingPlane::sampledCuttingPlane
     isoParams_
     (
         dict,
-        isoSurfaceParams::ALGO_POINT,
+        isoSurfaceParams::ALGO_TOPO,
         isoSurfaceParams::filterType::DIAGCELL
     ),
     average_(dict.getOrDefault("average", false)),

src/sampling/sampledSurface/sampledCuttingPlane/sampledCuttingPlane.H

@@ -56,8 +56,8 @@ Usage
         type     | cuttingPlane                             | yes |
         planeType | plane description (pointAndNormal etc)  | yes |
         mergeTol | tolerance for merging points             | no  | 1e-6
-        isoMethod | Iso-algorithm (cell/topo/point)         | no  | point
+        isoMethod | Iso-algorithm (cell/topo/point)         | no  | topo
-        regularise | point snapping (bool or enum)          | no  | true
+        regularise | Face simplification (enum or bool)     | no  | true
         bounds   | limit with bounding box                  | no  |
         zone     | limit to cell zone (name or regex)       | no  |
         zones    | limit to cell zones (names, regexs)      | no  |

src/sampling/surface/distanceSurface/distanceSurface.C

@@ -76,8 +76,7 @@ Foam::distanceSurface::distanceSurface
     isoParams_
     (
         dict,
-        isoSurfaceParams::ALGO_CELL,
+        isoSurfaceBase::ALGO_TOPO
-        isoSurfaceParams::filterType::DIAGCELL
     ),
     isoSurfCellPtr_(nullptr),
     isoSurfPointPtr_(nullptr),

src/sampling/surface/distanceSurface/distanceSurface.H

@@ -38,8 +38,8 @@ Usage
         Property | Description                              | Required | Default
         distance | distance from surface                    | yes |
         signed   | Use sign when distance is positive       | partly |
-        isoMethod | Iso-algorithm (cell/topo/point)         | no  | cell
+        isoMethod | Iso-algorithm (cell/topo/point)         | no  | topo
-        regularise | Point snapping (enum or bool)          | no  | true
+        regularise | Face simplification (enum or bool)     | no  | true
         bounds   | Limit with bounding box                  | no  |
         surfaceType | Type of surface                       | yes |
         surfaceName | Name of surface in \c triSurface/     | no  | dict name
@@ -57,6 +57,8 @@ Note
 The keyword \c cell (bool value) which was use in 1906 and earlier to switch
 between point/cell algorithms is now ignored (2020-12).
 
+Changed default algorithm from cell to topo (2020-12).
+
 SourceFiles
     distanceSurface.C
 
@@ -82,7 +84,7 @@ namespace Foam
 
 class distanceSurface
 {
-    // Private data
+    // Private Data
 
         //- Reference to mesh
         const polyMesh& mesh_;

src/sampling/surface/isoSurface/isoSurfaceBase.H

@@ -32,7 +32,7 @@ Description
     Some common dictionary properties:
     \table
         Property | Description                              | Required | Default
-        isoAlgorithm | (cell/topo/point)                    | no  | point
+        isoAlgorithm | (cell/topo/point)                    | no  | topo
         regularise | point snapping (bool or enum)          | no  | true
     \endtable