Importing Non-Native Models into Inventor

My friends from the DevTech group, which support the members of the Autodesk Developer Network (ADN), are helping me out while I’m buried with project work and are providing some content for blog posts.  This one is from Xiaodong Liang who works in the Beijing China office.

There are two basic mechanisms for importing non-native surface or solid bodies into Inventor. The first involves using the TransientBrep.ReadFromFile method to read a surface body in directly. The second mechanism involves using a suitable translator add-in to read the data in. In both cases the surface/solid data can then be added as a Part feature via the NonParametricFeatures.Add method.

This first code sample illustrates how to use the TransientBrep.ReadFromFile mechanism to read the model data from a SAT file:-

Sub importByBrep()
    ‘ Get the active part document
    Dim oDoc As PartDocument
    Set oDoc = ThisApplication.ActiveDocument

    ‘ Get transient Brep
    Dim oBrep As TransientBRep
    Set oBrep = ThisApplication.TransientBRep

    ‘ Get the surfacebodies
    Dim oSBs As SurfaceBodies
    Set oSBs = oBrep.ReadFromFile("c:\temp\test.sat")

    ‘ Get definition of current document
    Dim oActiveDocDef As PartComponentDefinition
    Set oActiveDocDef = oDoc.ComponentDefinition

    ‘ Add each surfacebody of imported file to
    ‘ NonParametricBaseFeatures
    Dim oSB As SurfaceBody
    For Each oSB In oSBs
        oActiveDocDef.Features.NonParametricBaseFeatures.Add oSB
    Next

    oDoc.Update
End Sub

This next code sample illustrates how to use one of the translator add-ins to read the relevant data in, again from a SAT file.

Sub ImportByTanstorAddin()
    ‘ Get the active part document
    Dim oActiveDoc As PartDocument
    Set oActiveDoc = ThisApplication.ActiveDocument

    ‘ Get definition of active part document
    Dim oActiveDocDef As PartComponentDefinition
    Set oActiveDocDef = oActiveDoc.ComponentDefinition

    ‘ Get SAT TranslatorAddIn
    Dim oAddin As TranslatorAddIn
    Set oAddin = ThisApplication.ApplicationAddIns.ItemById( _
                       "{89162634-02B6-11D5-8E80-0010B541CD80}")

    ‘ Create context for open 
    Dim oTransObjs As TransientObjects
    Set oTransObjs = ThisApplication.TransientObjects
    Dim oContext As TranslationContext
    Set oContext = oTransObjs.CreateTranslationContext
    oContext.Type = kDataDropIOMechanism

    ‘ Create option for open
    Dim oOptions As NameValueMap
    Set oOptions = oTransObjs.CreateNameValueMap

    ‘ Create DataMedium for open
    Dim oDataMedium As DataMedium
    Set oDataMedium = oTransObjs.CreateDataMedium
    Call oOptions.Add("ImportSolid", True)
    oDataMedium.fileName = "c:\temp\test.sat"

    ‘ Open the SAT file
    Dim oNewDoc As PartDocument
    Call oAddin.Open(oDataMedium, oContext, oOptions, oNewDoc)
    Dim oNewDocDef As PartComponentDefinition
    Set oNewDocDef = oNewDoc.ComponentDefinition

    ‘ Read the surfacebodies to the current document
    Dim oSB As SurfaceBody
    For Each oSB In oNewDocDef.SurfaceBodies
        oActiveDocDef.Features.NonParametricBaseFeatures.Add oSB
    Next

    ‘ Close the temp doc without saving
    oNewDoc.Close True
End Sub

What can be confusing about this is that reading multiple bodies from different files this way yields a solid for the first import, but surfaces for any further imports to the same Part document.  A solid is created if there are no other solids in the Part and a surface is created if there is at least one solid in the Part already. This was the behavior in Inventor when importing bodies interactively until the recent addition of support for multiple solid bodies in a single part.  The behavior of the method  NonParametricBaseFeatures.Add mimics the old behavior. 

There is a way to get the new behavior though. We can use a definition object to stipulate exactly what kind of model is imported (Solid or Surface). The CreateDefinition and AddByDefinition methods of the NonParametricBaseFeatures object were added in Inventor 2011 and support additional flexibility that the Add method doesn’t. CreateDefinition is used to create the relevant definition object, which then specifies the output type of the NonParametricBaseFeature (surface, solid, multiple solids or composite type). The code below illustrates how this can be used to import solids:-

Sub BatchImport()
    ImportEachFile "C:\temp\test.sat", 1
    ImportEachFile "C:\temp\test2.sat", 2
End Sub

Sub ImportEac
hFile(fileName As String, index As Integer)
    ‘ Get the active part document
    Dim oDoc As PartDocument
    Set oDoc = ThisApplication.ActiveDocument

    ‘ Get transient Brep
    Dim oBrep As TransientBRep
    Set oBrep = ThisApplication.TransientBRep

    ‘ Get the surfacebodies
    Dim oSBs As SurfaceBodies
    Set oSBs = oBrep.ReadFromFile(fileName)

    ‘ To transform the body
    Dim oTG As TransientGeometry
    Set oTG = ThisApplication.TransientGeometry
    Dim oMatrix As Matrix
    Set oMatrix = oTG.CreateMatrix()

    ‘ Move the body arbitrarily
    oMatrix.SetTranslation oTG.CreateVector( _
                                         index * 10, index * 10, 0) 
    Dim oTransObjs As TransientObjects
    Set oTransObjs = ThisApplication.TransientObjects
    Dim oObjColl As ObjectCollection
    Set oObjColl = oTransObjs.CreateObjectCollection()

    ‘ Add each surfacebody of imported file to ObjectCollection
    Dim oSB As SurfaceBody
    For Each oSB In oSBs
        oBrep.Transform oSB, oMatrix
        oObjColl.Add oSB
    Next

    ‘ Get definition of current document
    Dim oPartDef As PartComponentDefinition
    Set oPartDef = oDoc.ComponentDefinition
    Dim oFeatures As PartFeatures
    Set oFeatures = oPartDef.Features
    Dim oNPFD As NonParametricBaseFeatureDefinition
    Set oNPFD = oFeatures.NonParametricBaseFeatures.CreateDefinition

    ‘ Assign the ObjectCollection to the definition.
    oNPFD.BRepEntities = oObjColl

    ‘ Set the output type
    oNPFD.OutputType = kSolidOutputType

    ‘ Create the NonParametricBaseFeature using the definition.
    oPartDef.Features.NonParametricBaseFeatures.AddByDefinition oNPFD
End Sub

And there we have it! I hope this answers a few questions about importing solids into Inventor.