The [Create Simplified Part] actually creates a derived assembly for the new part document. You will firstly create DerivedAssemblyDefinition, and configure the relevant options, finally add it to the new part by DerivedAssemblyComponents.Add.
The following is a small code demo.
Sub CreateSimplifiedPart()
' Set a reference to the active assembly document
Dim oDoc As AssemblyDocument
Set oDoc = ThisApplication.ActiveDocument
Dim oDef As AssemblyComponentDefinition
Set oDef = oDoc.ComponentDefinition
' Create a new part document that will derive the assembly
Dim oPartDoc As PartDocument
Set oPartDoc = ThisApplication.Documents.Add(kPartDocumentObject, , True)
Dim oPartDef As PartComponentDefinition
Set oPartDef = oPartDoc.ComponentDefinition
Dim oDerivedAssemblyDef As DerivedAssemblyDefinition
Set oDerivedAssemblyDef = oPartDef.ReferenceComponents.DerivedAssemblyComponents.CreateDefinition(oDoc.FullDocumentName)
' Set various related options
oDerivedAssemblyDef.DeriveStyle = kDeriveAsSingleBodyNoSeams
oDerivedAssemblyDef.IncludeAllTopLevelWorkFeatures = kDerivedIncludeAll
oDerivedAssemblyDef.IncludeAllTopLevelSketches = kDerivedIncludeAll
oDerivedAssemblyDef.IncludeAllTopLeveliMateDefinitions = kDerivedExcludeAll
oDerivedAssemblyDef.IncludeAllTopLevelParameters = kDerivedExcludeAll
oDerivedAssemblyDef.ReducedMemoryMode = True
Call oDerivedAssemblyDef.SetHolePatchingOptions(kDerivedPatchAll)
Call oDerivedAssemblyDef.SetRemoveByVisibilityOptions(kDerivedRemovePartsAndFaces, 25)
' Create the shrinkwrap component
Dim oDerivedAssembly As DerivedAssemblyComponent
Set oDerivedAssembly = oPartDef.ReferenceComponents.DerivedAssemblyComponents.Add(oDerivedAssemblyDef)
'save the new part file
Call oPartDoc.SaveAs("c:\temp\newpart.ipt", False)
End Sub
