Working With Unconstrained Imported Assembly Components

Issue:

You've found a great 3D model on the web that you want to use in Inventor. It was originally created in some other 3D design software, but you were able to import it into Inventor. The problem is that the parts come in unconstrained and can move all over the place. Is there an option to import models from other software and keep the assembly constraints?

Solution:

There is no option to import the assembly constraints, but most likely you won't need to apply constraints to all of the parts because they have been imported in the correct orientation and location. Instead you can just ground all of the parts in place so that they will not move, and then un-ground and apply assembly constraints to just the parts that need to move or that you need to edit.

If the assembly has a lot of moving parts that need assembly constraints, you can un-ground and constrain one part at a time to keep everything from moving on you.

Here is a quick iLogic rule that will ground all components in place also.

' get the active assembly
Dim oAsmCompDef As AssemblyComponentDefinition
oAsmCompDef = ThisApplication.ActiveDocument.ComponentDefinition

'set the Master LOD active
Dim oLODRep As LevelofDetailRepresentation
oLODRep = oAsmCompDef.RepresentationsManager.LevelOfDetailRepresentations.Item("Master")
oLODRep.Activate

'Iterate through all of the occurrences and ground them.
Dim oOccurrence As ComponentOccurrence
For Each oOccurrence In oAsmCompDef.Occurrences
	'check for and skip virtual components
	If Not TypeOf oOccurrence.Definition Is VirtualComponentDefinition Then
		oOccurrence.Grounded = True
	Else
	End If
Next

Update : 
Here is an updated version of this rule that grounds everything in all assembly levels.

Sub Main

	Call TraverseAssembly(ThisDoc.Document.ComponentDefinition.Occurrences)

End Sub

Function TraverseAssembly(oOccs As ComponentOccurrences)
	Dim oOcc As ComponentOccurrence
	For Each oOcc In oOccs
		Try : oOcc.Grounded = True: Catch : End Try
		If oOcc.DefinitionDocumentType = DocumentTypeEnum.kAssemblyDocumentObject Then
			Call TraverseAssembly(oOcc.SubOccurrences)
		End If
	Next
End Function 

Another version that offers the user a choice to ground or unground:

Sub Main
	oOccs = ThisDoc.Document.ComponentDefinition.Occurrences
	oInput = InputRadioBox("Select one", "Ground All", "Unground All", True,"iLogic")
	Call TraverseAssembly(ThisDoc.Document.ComponentDefinition.Occurrences, oInput)
End Sub

Function TraverseAssembly(oOccs As ComponentOccurrences, oInput As Boolean)
	Dim oOcc As ComponentOccurrence
	For Each oOcc In oOccs
		Try : oOcc.Grounded = oInput : Catch : End Try
		If oOcc.DefinitionDocumentType = DocumentTypeEnum.kAssemblyDocumentObject Then
			Call TraverseAssembly(oOcc.SubOccurrences, oInput)
		End If
	Next
End Function