Implement dfAutoPatch: A tool to divide external faces into independent patches.

Author: TimoLin

applications/utilities/dfAutoPatch/Make/files

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+dfAutoPatch.C
+
+EXE = $(DF_APPBIN)/dfAutoPatch

applications/utilities/dfAutoPatch/Make/options

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+EXE_INC = \
+    -I$(LIB_SRC)/meshTools/lnInclude \
+    -I$(LIB_SRC)/dynamicMesh/lnInclude
+
+EXE_LIBS = \
+    -ldynamicMesh \
+    -lmeshTools

applications/utilities/dfAutoPatch/dfAutoPatch.C

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+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Application
+    dfAutoPatch
+
+Description
+    An extension of autoPatch to work with polyhedral meshes.
+    This utility divides external faces into patches based on (user supplied) feature
+    angle and the source patches can be limited to user supplied patches if desired.
+    The resulting patches are renamed to <originalName>_autoN if only a subset of 
+    patches is processed, otherwise to autoN.
+
+    Example usage:
+    dfAutoPatch -onlyPatches "(box)" 45
+
+Authorship
+    Author: Teng Zhang @ AISI, <ztnuaa0211@gmail.com>
+    Date: 2025-10-22
+\*---------------------------------------------------------------------------*/
+
+#include "argList.H"
+#include "polyMesh.H"
+#include "Time.H"
+#include "boundaryMesh.H"
+#include "repatchPolyTopoChanger.H"
+#include "unitConversion.H"
+#include "OFstream.H"
+#include "ListOps.H"
+#include "wordList.H"
+
+using namespace Foam;
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+// Get all feature edges.
+void collectFeatureEdges(const boundaryMesh& bMesh, labelList& markedEdges)
+{
+    markedEdges.setSize(bMesh.mesh().nEdges());
+
+    label markedI = 0;
+
+    forAll(bMesh.featureSegments(), i)
+    {
+        const labelList& segment = bMesh.featureSegments()[i];
+
+        forAll(segment, j)
+        {
+            label featEdgeI = segment[j];
+
+            label meshEdgeI = bMesh.featureToEdge()[featEdgeI];
+
+            markedEdges[markedI++] = meshEdgeI;
+        }
+    }
+    markedEdges.setSize(markedI);
+}
+
+
+
+int main(int argc, char *argv[])
+{
+    #include "addOverwriteOption.H"
+    argList::noParallel();
+    argList::validArgs.append("feature angle[0-180]");
+    argList::addOption
+    (
+        "onlyPatches",
+        "wordList of boundary patch names to be repatched"
+    );
+
+    #include "setRootCase.H"
+    #include "createTime.H"
+    runTime.functionObjects().off();
+    #include "createPolyMesh.H"
+    const word oldInstance = mesh.pointsInstance();
+
+    wordList onlyPatches;
+
+    if (args.optionFound("onlyPatches"))
+    {
+        onlyPatches = wordList(args.optionLookup("onlyPatches")());
+
+        Info<< "Limiting autoPatch to patches: " << onlyPatches
+            << nl << endl;
+    }
+
+    Info<< "Mesh read in = "
+        << runTime.cpuTimeIncrement()
+        << " s\n" << endl << endl;
+
+
+    const scalar featureAngle = args.argRead<scalar>(1);
+    const bool overwrite      = args.optionFound("overwrite");
+
+    const scalar minCos = Foam::cos(degToRad(featureAngle));
+
+    Info<< "Feature:" << featureAngle << endl
+        << "minCos :" << minCos << endl
+        << endl;
+
+    //
+    // Use boundaryMesh to reuse all the featureEdge stuff in there.
+    //
+
+    boundaryMesh bMesh;
+    bMesh.read(mesh);
+
+    // Set feature angle (calculate feature edges)
+    bMesh.setFeatureEdges(minCos);
+
+    // Collect all feature edges as edge labels
+    labelList markedEdges;
+
+    collectFeatureEdges(bMesh, markedEdges);
+
+
+
+    const labelList& boundaryFaces = bMesh.meshFace();
+    const polyBoundaryMesh& originalBoundary = mesh.boundaryMesh();
+    const label nBoundaryFaces = boundaryFaces.size();
+
+    // (new) patch ID for every face in mesh.
+    labelList patchIDs(nBoundaryFaces, -1);
+    boolList processFace(nBoundaryFaces, false);
+    labelList originalPatchIDs(nBoundaryFaces, -1);
+
+    // Track per-patch suffix when only a subset is processed.
+    labelList patchSuffixCount(originalBoundary.size(), 0);
+
+    const bool limitToPatches = onlyPatches.size() != 0;
+
+    // Determine which faces are allowed to be repatched.
+    forAll(boundaryFaces, facei)
+    {
+        const label meshFacei = boundaryFaces[facei];
+        const label patchi = originalBoundary.whichPatch(meshFacei);
+        const word& patchName = originalBoundary[patchi].name();
+
+        originalPatchIDs[facei] = patchi;
+        patchIDs[facei] = patchi;
+
+        if (!limitToPatches || findIndex(onlyPatches, patchName) != -1)
+        {
+            patchIDs[facei] = -1;
+            processFace[facei] = true;
+        }
+    }
+
+    if (limitToPatches)
+    {
+        label selectedFaceCount = 0;
+
+        forAll(processFace, facei)
+        {
+            if (processFace[facei])
+            {
+                ++selectedFaceCount;
+            }
+        }
+
+        if (!selectedFaceCount)
+        {
+            Info<< "No faces found for the supplied onlyPatches option." << nl
+                << endl;
+        }
+    }
+
+    //
+    // Fill patchIDs with values for every face by floodfilling without
+    // crossing feature edge.
+    //
+
+    // Current patch number.
+    label newPatchi = bMesh.patches().size();
+
+    label suffix = 0;
+
+    while (true)
+    {
+        // Find first unset face respecting the optional patch filter.
+        label unsetFacei = -1;
+
+        forAll(patchIDs, facei)
+        {
+            if (patchIDs[facei] == -1 && processFace[facei])
+            {
+                unsetFacei = facei;
+                break;
+            }
+        }
+
+        if (unsetFacei == -1)
+        {
+            // All faces have patchID set. Exit.
+            break;
+        }
+
+        // Found unset face. Create patch for it.
+        word patchName;
+        if (limitToPatches)
+        {
+            const label basePatchi = originalPatchIDs[unsetFacei];
+            const word& baseName = originalBoundary[basePatchi].name();
+            label& nextSuffix = patchSuffixCount[basePatchi];
+
+            do
+            {
+                patchName = baseName + "_auto" + name(nextSuffix++);
+            }
+            while (bMesh.findPatchID(patchName) != -1);
+        }
+        else
+        {
+            do
+            {
+                patchName = "auto" + name(suffix++);
+            }
+            while (bMesh.findPatchID(patchName) != -1);
+        }
+
+        bMesh.addPatch(patchName);
+
+        bMesh.changePatchType(patchName, "patch");
+
+
+        // Fill visited with all faces reachable from unsetFacei.
+        boolList visited(nBoundaryFaces, false);
+
+        bMesh.markFaces(markedEdges, unsetFacei, visited);
+
+
+        // Assign all visited faces to current patch
+        label nVisited = 0;
+
+        forAll(visited, facei)
+        {
+            if (visited[facei] && processFace[facei])
+            {
+                nVisited++;
+
+                patchIDs[facei] = newPatchi;
+            }
+        }
+
+        Info<< "Assigned " << nVisited << " faces to patch " << patchName
+            << endl << endl;
+
+        newPatchi++;
+    }
+
+
+
+    const PtrList<boundaryPatch>& patches = bMesh.patches();
+
+    // Create new list of patches with old ones first
+    List<polyPatch*> newPatchPtrList(patches.size());
+
+    newPatchi = 0;
+
+    // Copy old patches
+    forAll(mesh.boundaryMesh(), patchi)
+    {
+        const polyPatch& patch = mesh.boundaryMesh()[patchi];
+
+        newPatchPtrList[newPatchi] =
+            patch.clone
+            (
+                mesh.boundaryMesh(),
+                newPatchi,
+                patch.size(),
+                patch.start()
+            ).ptr();
+
+        newPatchi++;
+    }
+
+    // Add new ones with empty size.
+    for (label patchi = newPatchi; patchi < patches.size(); patchi++)
+    {
+        const boundaryPatch& bp = patches[patchi];
+
+        newPatchPtrList[newPatchi] = polyPatch::New
+        (
+            polyPatch::typeName,
+            bp.name(),
+            0,
+            mesh.nFaces(),
+            newPatchi,
+            mesh.boundaryMesh()
+        ).ptr();
+
+        newPatchi++;
+    }
+
+    if (!overwrite)
+    {
+        runTime++;
+    }
+
+
+    // Change patches
+    repatchPolyTopoChanger polyMeshRepatcher(mesh);
+    polyMeshRepatcher.changePatches(newPatchPtrList);
+
+
+    // Change face ordering
+
+    // Since bMesh read from mesh there is one to one mapping so we don't
+    // have to do the geometric stuff.
+    forAll(patchIDs, facei)
+    {
+        label meshFacei = boundaryFaces[facei];
+
+        polyMeshRepatcher.changePatchID(meshFacei, patchIDs[facei]);
+    }
+
+    polyMeshRepatcher.repatch();
+
+    // Write resulting mesh
+    if (overwrite)
+    {
+        mesh.setInstance(oldInstance);
+    }
+
+    // Set the precision of the points data to 10
+    IOstream::defaultPrecision(max(10u, IOstream::defaultPrecision()));
+
+    mesh.write();
+
+    Info<< "End\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //