ICEM-CFD Advanced Tetra Part I Geometry Repair.ppt

AdvancedTetraHalfDayPartI GeometryRepair Overview BasicTetraOverviewSTLRepairCADRepairTetraRepairMakeConsistentAdvancedPrismandRepairTetratoHexa TetraApproach or WhattheHeckisanOctree MeshsizeinformationisprescribedongeometryUnderlyingmeshfillboundingboxMeshissubdividedtoconformtogeometrydividedinhalfinthreedimensions henceOctreeSizesbypowersof2 FurtheradjustwithreferencesizeWantelementssize10 surfaceparamsize8 x referencesize1 25 meshsize10 CutterprocessdeterminesboundarysurfaceelementsSurfacemeshisaresultofthevolumemeshSmoothingachievesgoodelementquality OverallProcessOverview CreateorimportgeometryRepairgeometryDefinemeshsizegloballyandonselectedentitiesGeneratethemeshImprovethemesh smoothing etc HybridizethemeshasdesiredImprovethemeshagain smoothing etc Exporttoanalysissoftware GeometryforTetra RequiresanenclosedsurfacemodelDisplaysurfacesassolidlookformissingsurfaceslookforholesorgapsvisuallyLookforholesorgapshighlightedusingbuildtopologyTetracantoleratesmallgaps inrelationtolocalelementsize PointsandcurvesatkeyfeaturesMaterialpointstodefinevolumes Missinginletsurface UsingPointsandCurves IncludepointsatsharpcornersIncludecurvestoforcenodestobeplacedatkeyfeaturesatsurfaceintersectionsat kinks insurfacesDonotincludecurveswheresurfacesmeetsmoothlyNOTE failingtoincludepointsandcurveswillresultinmeshwhichis chamfered atcorners UsingPointsandCurves Example PointsatCorners CurvesatEdgesofSurfaces Resultwithpointsandcurves Resultwithoutpointsandcurves TetraProcessOverview RunTetramesherproducesuncutdomainRunCutterperforms floodfill frommaterialpoint s producescutdomainRunSmootherRunCoarsener Separateexecutables canberuninteractivelyorinbatchmode Tetra BatchVs Interactive Usebatchmodewith clean geometrynoleakageexpected4 2maybethebeginningoftheendforInteractiveInteractivemodeallowsusertoviewandrepairproblemssurfacemeshwillbedisplayedifTetrafindsaclosedvolumeleakageindicatedwhenajaggedlineappearsindisplay TetraHands onSession 1 FacetedGeometryRepair ImportingtheFacetedData TheUseofFaceteddataiscommonICEMCFDcanconvertsurfacedatafrommanyformats includingSTL RepairFacetedData STLDatacomesinasonesurfaceandoneFamily UseSegmentSurface RepairFacetedData Segmentthesurfacebyangle Wherethereisachangeindirectionofthesurfacegreaterthantheangle thesurfacewillbesegmented Surface ChangeFamily Itisusefultobreakthepartintosurfacefamilies Turnon offvariousfamiliesforeasiervisualizationSelections suchas setmeshparameters basedonfamiliesGrowPrismfromcertainfamiliesSetboundaryconditionsbyfamily Thepartshavebeensegmented Assignfamilynamestothesurfacesforeachpart Re Segment ContinuewithChangeFamily Surfacerequiresfurthersegmentation UseSmallerAngle Familyedit FamilyColorsareassigned ThiscanbechangedusingtheFamilyeditmenu Editbuttonintoprightofscreen Colorscanbechangedindividuallyorwith Goodcolors Familynamefieldscanbeedited FacetedDataRepair 2Repairmodes CADDataFacetedDataGeneratesCurvesBasedonsurfacegaptolerance BuildTopology Curvesare coloredbycount withinatoleranceYellow SingleSurfacemeetsatthatedgewithinthetoleranceOftenindicatesagaporhole Red 2surfacesmeetatthatedgeUsuallymeans watertight Blue MultipleSurfacesmeetCanbeaproblem dependingonsolver Canalsoindicateduplicatesurfaces Green UnattachedcurvesCareful deletedif allfamilies isselectedGapscanbestitched Holescanbefilled StitchEdges Gapgreaterthan0 01indicatedbyyellowcurves UseStitchedges andcheck selectusingcurves Stitchedges Selectthe2curveswhichrepresenteachsideofthegap Aftertheyturnwhite middlemousebutton StitchEdges ThesurfaceTrielementsonbothsurfacesaredivideduntiltheycanbelinedupnodefornodewiththetrielementsacrossthegap Thecurveturnsredtoindicatethatthetwosurfacesnowmeetwithintolerance WhenStitchedgefails Duetothesegmentednatureofthiscurve stitchingthisedgecorruptsthesurface Note UndoisnotavailableSavefrequentlyduringgeometryrepair Tetinfile Unload Occasionally itisnecessarytounloadatetinfileordomainfileandloadapreviousversion SurfaceDelete Surfacehasotherproblems BestSolution Deletethesurfaceandre createit CloseHoles RebuildTopologyCloseHolesSelectusingCurvesAddNodesSelecttheouterandinnerholes Closeholes Boundarynodesarenumbered Internalnodesandsurfacetri sareadded Re SegmentSurface AfterClosingtheholes thecylinderbecomesonesurface Buildtopologywillnolongercreatecurves Meshwillbe chamfered atedges NeedtoSegmentsurfaces Closeholes Thereareseveraltri smissingfromthevalveUsecloseholes without selectusingcurves ManipulatingTri s Surfacewassegmented sodeletethissurface Tip Turnoff seat family FoldedSurfaceTri s DeleteTriangles Deletetheoverlappingtriangles CreateTriangles Holeinsurfaceneedstobefilled MergeNodes Redcurvesaretheresultofpartiallysegmentedsurface Solution mergenodes Defaulttoleranceis1 ofshortestedgelength Ortypeinyourowntolerance Closeholeonnon planarsurface Thisedgehasadifficultgaptofix Instead deletethissurface Closeholes Using Closeholes Selectbothcurves andcurvesegments Closeholes Gapisclosed Don tforgettosegmentsurfaceifneeded TetraHands onSession 2 CadDataRepair CADCreateTopology SlightlydifferentGUIYellowcurveshighlightgapsandholes CloseHole ToCloseaholeorreplaceamissingsurface CreateTopologySelect Closehole Selecttheboundingcurve s MMB Closehole ICEMCFDShowsyouapreviewofthesurface SeenbestwithablackbackgroundType y toaccept Closemultiplegaps Frequently therearemultiplegaps Use Closemultiplegaps insteadofre selectingthe Closegap commandrepeatedly Stitchmultiplegaps Windowselectagroupofcurves Pairbypair theuserispromptedforthemethodofgaprepair andthenaskedtoapprovetheproposedsolution Cycleendswhenallgapshavebeenrepairedorskipped Options n nochange skiptothenextpairf fill createasurfacethatstretchesfromonecurvetotheother originalsurfacesuntouchedb blend similartofill butcurvesthesurfacetangentialwithboundingsurfaces t trim fortrimmedsurfaces recalculatestheintersection m match thesecondsurfaceedgeismovedtothefirstA auto selectsthebestoffilltrimormatchx cancel Closegap Closegapalsoworksinsinglegapmode Closegap Closegappromptstheuser Firstselectthecurvesoneithersideofthegap T