As part of the SelectionItem class in HPS, there is the function ShowSelectionPosition():
https://docs.techsoft3d.com/hps/latest/build/api_ref/cppcs/class_h_p_s_1_1_selection_item.html#a2d821f505f2129668bd6aad1cb225440.html?highlight=showselectionposition#function-HPS.SelectionItem.ShowSelectionPosition
Depending on the variant of the function, it will return a WindowPoint or WorldPoint.
To demonstrate getting a WorldPoint, below is a code snippet that can be executed in the hps_mfc_sandbox Visual Studio project found in the directory:
HOOPS_Visualize_202X\samples\mfc_sandbox
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