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#!/usr/bin/env python
## Program: VMTK
## Module: $RCSfile: vmtkmeshgenerator.py,v $
## Language: Python
## Date: $Date: 2006/02/23 09:27:52 $
## Version: $Revision: 1.7 $
## Copyright (c) Luca Antiga, David Steinman. All rights reserved.
## See LICENCE file for details.
## This software is distributed WITHOUT ANY WARRANTY; without even
## the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
## PURPOSE. See the above copyright notices for more information.
import vtk
import vtkvmtk
import sys
import vmtkscripts
import pypes
vmtkmeshgenerator = 'vmtkMeshGenerator'
class vmtkMeshGenerator(pypes.pypeScript):
def __init__(self):
pypes.pypeScript.__init__(self)
self.Surface = None
self.TargetEdgeLength = 1.0
self.TargetEdgeLengthFactor = 1.0
self.TargetEdgeLengthArrayName = ''
self.MaxEdgeLength = 1E16
self.MinEdgeLength = 0.0
self.TriangleSplitFactor = 5.0
self.CellEntityIdsArrayName = 'CellEntityIds'
self.ElementSizeMode = 'edgelength'
self.VolumeElementScaleFactor = 0.8
self.CappingMethod = 'simple'
self.SkipCapping = 0
self.RemeshCapsOnly = 0
self.SkipRemeshing = 0
self.EndcapsEdgeLengthFactor = 1.0
self.BoundaryLayer = 0
self.NumberOfSubLayers = 2
self.SubLayerRatio = 0.5
self.BoundaryLayerThicknessFactor = 0.25
self.NumberOfSubsteps = 2000
self.Relaxation = 0.01
self.LocalCorrectionFactor = 0.45
self.Tetrahedralize = 0
self.BoundaryLayerOnCaps = 1
self.SizingFunctionArrayName = 'VolumeSizingFunction'
self.Mesh = None
self.RemeshedSurface = None
self.SetScriptName('vmtkmeshgenerator')
self.SetScriptDoc('generate a mesh suitable for CFD from a surface')
self.SetInputMembers([
['Surface','i','vtkPolyData',1,'','the input surface','vmtksurfacereader'],
['TargetEdgeLength','edgelength','float',1,'(0.0,)'],
['TargetEdgeLengthArrayName','edgelengtharray','str',1],
['TargetEdgeLengthFactor','edgelengthfactor','float',1,'(0.0,)'],
['TriangleSplitFactor','trianglesplitfactor','float',1,'(0.0,)'],
['EndcapsEdgeLengthFactor','endcapsedgelengthfactor','float',1,'(0.0,)'],
['MaxEdgeLength','maxedgelength','float',1,'(0.0,)'],
['MinEdgeLength','minedgelength','float',1,'(0.0,)'],
['CellEntityIdsArrayName','entityidsarray','str',1],
['ElementSizeMode','elementsizemode','str',1,'["edgelength","edgelengtharray"]'],
['CappingMethod','cappingmethod','str',1,'["simple","annular","concaveannular"]'],
['SkipCapping','skipcapping','bool',1,''],
['SkipRemeshing','skipremeshing','bool',1,''],
['VolumeElementScaleFactor','volumeelementfactor','float',1,'(0.0,)'],
['BoundaryLayer','boundarylayer','bool',1,''],
['NumberOfSubLayers','sublayers','int',1,'(0,)'],
['NumberOfSubsteps','substeps','int',1,'(0,)'],
['Relaxation','relaxation','float',1,'(0.0,)'],
['LocalCorrectionFactor','localcorrection','float',1,'(0.0,)'],
['SubLayerRatio','sublayerratio','float',1,'(0.0,)'],
['BoundaryLayerThicknessFactor','thicknessfactor','float',1,'(0.0,)'],
['RemeshCapsOnly','remeshcapsonly','bool',1,''],
['BoundaryLayerOnCaps','boundarylayeroncaps','bool',1,''],
['Tetrahedralize','tetrahedralize','bool',1,'']
])
self.SetOutputMembers([
['Mesh','o','vtkUnstructuredGrid',1,'','the output mesh','vmtkmeshwriter'],
['CellEntityIdsArrayName','entityidsarray','str',1],
['RemeshedSurface','remeshedsurface','vtkPolyData',1,'','the output surface','vmtksurfacewriter'],
])
def Execute(self):
if self.Surface == None:
self.PrintError('Error: No input surface.')
wallEntityOffset = 1
if self.SkipCapping or not self.BoundaryLayerOnCaps:
self.PrintLog("Not capping surface")
surface = self.Surface
cellEntityIdsArray = vtk.vtkIntArray()
cellEntityIdsArray.SetName(self.CellEntityIdsArrayName)
cellEntityIdsArray.SetNumberOfTuples(surface.GetNumberOfCells())
cellEntityIdsArray.FillComponent(0,0.0)
surface.GetCellData().AddArray(cellEntityIdsArray)
else:
self.PrintLog("Capping surface")
capper = vmtkscripts.vmtkSurfaceCapper()
capper.Surface = self.Surface
capper.Interactive = 0
capper.Method = self.CappingMethod
capper.TriangleOutput = 0
capper.CellEntityIdOffset = wallEntityOffset
capper.Execute()
surface = capper.Surface
if self.SkipRemeshing:
remeshedSurface = surface
else:
self.PrintLog("Remeshing surface")
remeshing = vmtkscripts.vmtkSurfaceRemeshing()
remeshing.Surface = surface
remeshing.CellEntityIdsArrayName = self.CellEntityIdsArrayName
remeshing.TargetEdgeLength = self.TargetEdgeLength
remeshing.MaxEdgeLength = self.MaxEdgeLength
remeshing.MinEdgeLength = self.MinEdgeLength
remeshing.TargetEdgeLengthFactor = self.TargetEdgeLengthFactor
remeshing.TargetEdgeLengthArrayName = self.TargetEdgeLengthArrayName
remeshing.TriangleSplitFactor = self.TriangleSplitFactor
remeshing.ElementSizeMode = self.ElementSizeMode
if self.RemeshCapsOnly:
remeshing.ExcludeEntityIds = [wallEntityOffset]
remeshing.Execute()
remeshedSurface = remeshing.Surface
if self.BoundaryLayer:
projection = vmtkscripts.vmtkSurfaceProjection()
projection.Surface = remeshedSurface
projection.ReferenceSurface = surface
projection.Execute()
normals = vmtkscripts.vmtkSurfaceNormals()
normals.Surface = projection.Surface
normals.NormalsArrayName = 'Normals'
normals.Execute()
surfaceToMesh = vmtkscripts.vmtkSurfaceToMesh()
surfaceToMesh.Surface = normals.Surface
surfaceToMesh.Execute()
self.PrintLog("Generating boundary layer")
placeholderCellEntityId = 9999
boundaryLayer = vmtkscripts.vmtkBoundaryLayer()
boundaryLayer.Mesh = surfaceToMesh.Mesh
boundaryLayer.WarpVectorsArrayName = 'Normals'
boundaryLayer.NegateWarpVectors = True
boundaryLayer.ThicknessArrayName = self.TargetEdgeLengthArrayName
if self.ElementSizeMode == 'edgelength':
boundaryLayer.ConstantThickness = True
else:
boundaryLayer.ConstantThickness = False
boundaryLayer.IncludeSurfaceCells = 0
boundaryLayer.NumberOfSubLayers = self.NumberOfSubLayers
boundaryLayer.NumberOfSubsteps = self.NumberOfSubsteps
boundaryLayer.Relaxation = self.Relaxation
boundaryLayer.LocalCorrectionFactor = self.LocalCorrectionFactor
boundaryLayer.SubLayerRatio = self.SubLayerRatio
boundaryLayer.Thickness = self.BoundaryLayerThicknessFactor * self.TargetEdgeLength
boundaryLayer.ThicknessRatio = self.BoundaryLayerThicknessFactor * self.TargetEdgeLengthFactor
boundaryLayer.MaximumThickness = self.BoundaryLayerThicknessFactor * self.MaxEdgeLength
if not self.BoundaryLayerOnCaps:
boundaryLayer.SidewallCellEntityId = placeholderCellEntityId
boundaryLayer.InnerSurfaceCellEntityId = wallEntityOffset
boundaryLayer.Execute()
meshToSurface = vmtkscripts.vmtkMeshToSurface()
meshToSurface.Mesh = boundaryLayer.InnerSurfaceMesh
meshToSurface.Execute()
innerSurface = meshToSurface.Surface
if not self.BoundaryLayerOnCaps:
self.PrintLog("Capping inner surface")
capper = vmtkscripts.vmtkSurfaceCapper()
capper.Surface = innerSurface
capper.Interactive = 0
capper.Method = self.CappingMethod
capper.TriangleOutput = 1
capper.CellEntityIdOffset = wallEntityOffset
capper.Execute()
self.PrintLog("Remeshing endcaps")
remeshing = vmtkscripts.vmtkSurfaceRemeshing()
remeshing.Surface = capper.Surface
remeshing.CellEntityIdsArrayName = self.CellEntityIdsArrayName
remeshing.TargetEdgeLength = self.TargetEdgeLength * self.EndcapsEdgeLengthFactor
remeshing.MaxEdgeLength = self.MaxEdgeLength
remeshing.MinEdgeLength = self.MinEdgeLength
remeshing.TargetEdgeLengthFactor = self.TargetEdgeLengthFactor * self.EndcapsEdgeLengthFactor
remeshing.TargetEdgeLengthArrayName = self.TargetEdgeLengthArrayName
remeshing.TriangleSplitFactor = self.TriangleSplitFactor
remeshing.ElementSizeMode = self.ElementSizeMode
remeshing.ExcludeEntityIds = [wallEntityOffset]
remeshing.Execute()
innerSurface = remeshing.Surface
self.PrintLog("Computing sizing function")
sizingFunction = vtkvmtk.vtkvmtkPolyDataSizingFunction()
sizingFunction.SetInputData(innerSurface)
sizingFunction.SetSizingFunctionArrayName(self.SizingFunctionArrayName)
sizingFunction.SetScaleFactor(self.VolumeElementScaleFactor)
sizingFunction.Update()
surfaceToMesh2 = vmtkscripts.vmtkSurfaceToMesh()
surfaceToMesh2.Surface = sizingFunction.GetOutput()
surfaceToMesh2.Execute()
self.PrintLog("Generating volume mesh")
tetgen = vmtkscripts.vmtkTetGen()
tetgen.Mesh = surfaceToMesh2.Mesh
tetgen.GenerateCaps = 0
tetgen.UseSizingFunction = 1
tetgen.SizingFunctionArrayName = self.SizingFunctionArrayName
tetgen.CellEntityIdsArrayName = self.CellEntityIdsArrayName
tetgen.Order = 1
tetgen.Quality = 1
tetgen.PLC = 1
tetgen.NoBoundarySplit = 1
tetgen.RemoveSliver = 1
tetgen.OutputSurfaceElements = 0
tetgen.OutputVolumeElements = 1
tetgen.Execute()
#w = vtk.vtkXMLUnstructuredGridWriter()
#w.SetInput(tetgen.Mesh)
#w.SetFileName('tet.vtu')
#w.Write()
if tetgen.Mesh.GetNumberOfCells() == 0 and surfaceToMesh.Mesh.GetNumberOfCells() > 0:
self.PrintLog('An error occurred during tetrahedralization. Will only output surface mesh and boundary layer.')
surfaceToMesh.Mesh.GetCellData().GetArray(self.CellEntityIdsArrayName).FillComponent(0,wallEntityOffset)
self.PrintLog("Assembling final mesh")
appendFilter = vtkvmtk.vtkvmtkAppendFilter()
appendFilter.AddInputData(surfaceToMesh.Mesh)
appendFilter.AddInputData(boundaryLayer.Mesh)
appendFilter.AddInputData(tetgen.Mesh)
#appendFilter.AddInput(boundaryLayer.InnerSurfaceMesh)
if not self.BoundaryLayerOnCaps:
threshold = vtk.vtkThreshold()
threshold.SetInputData(surfaceToMesh2.Mesh)
threshold.ThresholdByUpper(1.5)
threshold.SetInputArrayToProcess(0,0,0,1,self.CellEntityIdsArrayName)
threshold.Update()
endcaps = threshold.GetOutput()
appendFilter.AddInputData(endcaps)
appendFilter.Update()
self.Mesh = appendFilter.GetOutput()
if not self.BoundaryLayerOnCaps:
cellEntityIdsArray = self.Mesh.GetCellData().GetArray(self.CellEntityIdsArrayName)
def VisitNeighbors(i, cellEntityId):
cellPointIds = vtk.vtkIdList()
self.Mesh.GetCellPoints(i,cellPointIds)
neighborPointIds = vtk.vtkIdList()
neighborPointIds.SetNumberOfIds(1)
pointNeighborCellIds = vtk.vtkIdList()
neighborCellIds = vtk.vtkIdList()
for j in range(cellPointIds.GetNumberOfIds()):
neighborPointIds.SetId(0,cellPointIds.GetId(j))
self.Mesh.GetCellNeighbors(i,neighborPointIds,pointNeighborCellIds)
for k in range(pointNeighborCellIds.GetNumberOfIds()):
neighborCellIds.InsertNextId(pointNeighborCellIds.GetId(k))
for j in range(neighborCellIds.GetNumberOfIds()):
cellId = neighborCellIds.GetId(j)
neighborCellEntityId = cellEntityIdsArray.GetTuple1(cellId)
neighborCellType = self.Mesh.GetCellType(cellId)
if neighborCellType not in [vtk.VTK_TRIANGLE, vtk.VTK_QUADRATIC_TRIANGLE, vtk.VTK_QUAD]:
continue
if neighborCellEntityId != placeholderCellEntityId:
continue
cellEntityIdsArray.SetTuple1(cellId,cellEntityId)
VisitNeighbors(cellId,cellEntityId)
for i in range(self.Mesh.GetNumberOfCells()):
cellEntityId = cellEntityIdsArray.GetTuple1(i)
cellType = self.Mesh.GetCellType(i)
if cellType not in [vtk.VTK_TRIANGLE, vtk.VTK_QUADRATIC_TRIANGLE, vtk.VTK_QUAD]:
continue
if cellEntityId in [0, 1, placeholderCellEntityId]:
continue
VisitNeighbors(i,cellEntityId)
else:
self.PrintLog("Computing sizing function")
sizingFunction = vtkvmtk.vtkvmtkPolyDataSizingFunction()
sizingFunction.SetInputData(remeshedSurface)
sizingFunction.SetSizingFunctionArrayName(self.SizingFunctionArrayName)
sizingFunction.SetScaleFactor(self.VolumeElementScaleFactor)
sizingFunction.Update()
self.PrintLog("Converting surface to mesh")
surfaceToMesh = vmtkscripts.vmtkSurfaceToMesh()
surfaceToMesh.Surface = sizingFunction.GetOutput()
surfaceToMesh.Execute()
self.PrintLog("Generating volume mesh")
tetgen = vmtkscripts.vmtkTetGen()
tetgen.Mesh = surfaceToMesh.Mesh
tetgen.GenerateCaps = 0
tetgen.UseSizingFunction = 1
tetgen.SizingFunctionArrayName = self.SizingFunctionArrayName
tetgen.CellEntityIdsArrayName = self.CellEntityIdsArrayName
tetgen.Order = 1
tetgen.Quality = 1
tetgen.PLC = 1
tetgen.NoBoundarySplit = 1
tetgen.RemoveSliver = 1
tetgen.OutputSurfaceElements = 1
tetgen.OutputVolumeElements = 1
tetgen.Execute()
self.Mesh = tetgen.Mesh
if self.Mesh.GetNumberOfCells() == 0 and surfaceToMesh.Mesh.GetNumberOfCells() > 0:
self.PrintLog('An error occurred during tetrahedralization. Will only output surface mesh.')
self.Mesh = surfaceToMesh.Mesh
if self.Tetrahedralize:
tetrahedralize = vtkvmtk.vtkvmtkUnstructuredGridTetraFilter()
tetrahedralize.SetInputData(self.Mesh)
tetrahedralize.Update()
self.Mesh = tetrahedralize.GetOutput()
self.RemeshedSurface = remeshedSurface
if __name__=='__main__':
main = pypes.pypeMain()
main.Arguments = sys.argv
main.Execute()
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