When Inventor opens the document in visible mode it makes the document active and displays it in active view. At this momemt you may change active view properties as desired.
Try the following rule:
Dim oView As View = ThisApplication.ActiveView
oView.DisplayMode = DisplayModeEnum.kShadedWithEdgesRendering
oView.Update
Then make this rule triggered by the event “After Open Document”.
Note that Inventor document object has the collection of views, so you may also change properties of View objects in the collection Document.Views.
DisplayModeEnum constants are discribed in the Inventor Programming Help:
kHiddenEdgeRendering, kIllustrationRendering, kMonochromeRendering,
kRealisticRendering, kShadedRendering, kShadedWithEdgesRendering, kShadedWithHiddenEdgesRendering, kWatercolorRendering, kWireframeNoHiddenEdges, kWireframeRendering, kWireframeWithHiddenEdgesRendering
Vladimir Ananyev
Developer Technical Services
Autodesk Developer Network