The code below works fine when swPart is defined as a generic object, and when I use the TypeName function to get the specific type of object, VBA tells me that it is a "PartDoc".  However, the code below produces the error shown in the screenshot when it is compiled.

Option Explicit

Sub Test()

Dim swApp As SldWorks.SldWorks, swPart As PartDoc

Set swApp = Application.SldWorks

Set swPart = swApp.ActivateDoc("Example.sldprt")

Debug.Print swPart.SetMaterialPropertyName("Custom Materials.sldmat", "Stainless Steel (ferritic)")

End Sub

The error:

Clicking "Okay" puts the editor in debug mode and highlights ".SetMaterialPropertyName".  So my question is, why can't I assign swPart to the class that it ends up being anyhow?