简介:Triangulationiswidelyusedinscientificresearch,suchasfiniteelementmeshgeneration,surfacereconstructionandthereconstructionofthedensityfielddata.Thispaperproposesanewmethodcombiningimageprocessinganddensity-controlledCentroidalVoronoitessellationstoquicklygenerateadensity-controlledconstrainedDelaunaytriangulationfor2Dseaarea.Firstly,preprocessdigitalimagesoftheseaareaandextracttheboundaryofseawaterregionbyeight-neighborsearchingalgorithm.Then,Iuse"Odd-EvenTesting"methodtocheckifonerandomvertexisinsidetheboundaryandinsertrandomverticesintotheboundary.Finally,wegettheCDTofrandomverticesbydensity-controlledCVT-Lloydmethod.Wealsogivesomecomparisonswithexistingmethods,andourmethodperformsbetterinfinalresultoftriangulation.
简介:WormandwormgeararemodeledunderdevelopmentenvironmentinAutoCADbasedontheprincipleofordinarycylindricalwormdrive.ThedrawingcommandsavailableinAutoCADareusedtodevelopwormblankandcuttermodels.Thesolidmodelsofwormandwormgearareobtainedthroughtheuseofthecommands,move,rotateandsubtract,tosimulatethegeneratingcuttingmovementonthegearcuttingmachine.Autolisplanguageisutilizedinprogrammingforparametricmodelingofwormandwormgear.Thedevelopedprogramcanautomaticallydrawwormandwormgearwhenusersloadthewlwgprogram,inputthemodulusandthenumberofthreads,handedness,andotherparameters.Theoperationissimpleandaccurate,providingpotentialstospeedupproductdesignprocessandimproveefficiency.
简介:3Dobjectscanbestoredincomputerofdifferentdescribingways,suchaspointset,polyline,polygonalsurfaceandEuclideandistancemap.Momentinvariantsofdifferentordersmayhavethedifferentmagnitude.Amethodfornormalizingmomentsof3Dobjectsisproposed,whichcansetthevaluesofmomentsofdifferentordersroughlyinthesamerangeandbeappliedtodifferent3Ddataformatsuniversally.Thenaccuratecomputationofmomentsforseveralobjectsispresentedandexperimentsshowthatthiskindofnormalizationisveryusefulformomentinvariantsin3Dobjectsanalysisandrecognition.
简介:Basedonthenecessityofthreedimensionalmodelingwithcomputerinteachingreform,thispaperisthesummarizationofreformpracticeofteachingengineeringdrawinginourinstitute.Theteachingreformbeginswiththreedimensionalmodelingthatusedcomputerinsteadofboard.Onthebasisoftargetofteachingreform,setofteachingcontent,arrangementofclasshourandteachingmethod,theresearchofteachingpracticehavebeendone,andverygoodeffectsinteachingofengineeringdrawinghavebeenachieved.
简介:Theconstructionofhigh-filledloessprojecthassomeengineeringandtechnicalchallenges,suchasexcavationofearthandbackfillingofeartharebothlarge,complexconstructionenvironment,varietyofinfluencefactors.Accordingtothissituation,thispaperpresentsadynamic3Dvisualizationmethodforhigh-filledprojectbasedonvolumerendering.Throughcomparativeanalysisandvisualanalysis,realizedatdifferenttimesoftheLoessfillinternaldetectiondatavisualizationandanalysispresented.Theresultsshowthatthisvisualizationmethodcandirectlyandaccuratelydisplaytheconstructionprocess,helpdecisionmakersmasterconstructioninformationandprocess.
简介:In3Dmodelsretrieval,featuredescriptionandretrievalofnon-rigidmodelfacemorecomplexproblemsduetotheisometrytransformationofitself.Weintroducethehierarchicalcombinationmatchingintothefeaturecomparison,andbuildamapbetweenthedividedregionsoftwomodels,andthenachieveaccuratefeaturematchingbasedonpatch-by-patch,whichsuccessfullyintroducesthespatialinformationintofeaturematching.Verifiedbyexperiment,the3Dmodelretrievalmethodproposedinthispaperbasedonhierarchicalcombinationmatchingcanmakesuremoreaccuratefeaturematching,soastoenhancetheprecisionofretrieval.