Hi @T.Nakamura,
currently you can use the tracking event to check the tracking status
So first you need in the 3D container widget to enable the tracking events ,Extended tracking and Persist Map ( so far I remember - on mobile only - on the HoloLens they are set by default ) and then in the ModelTarget widget you can use the event Tracking Acquired and Tracking Lost events were you can via script set some properties e.g. set specific shader or load specific model (e.g. model containing only some parts on the Assembly , possibly boundary in specific color or you could set specific color. (e.g. you can find in the help http://support.ptc.com/help/vuforia/studio/en/#page/Studio_Help_Center%2Fmetadata%2FMetadata_201_Highlight_Parts.html%23wwID0EQJRT )
Currently we do not have an edge highlight property or shader (or other kind of wireframe shader) so currently you can use for highlight only specific shader with colors or set a value of 3d label informing about the tracking status
The PTC R&D already works on such implementation but so far I understood it is not trivial and will need some time to be implemented. The already reported in the past related issue is the Jira Ticket STUD-3480. So I reported now your request to the PTC R&D and Product Management team as Jira VTS-1186 and linked it to the already existing related topic STUD-3480. When there is some feedback form R&D I will post this here. Thanks! Best Regards
