You can customize the orientation by specifying a front and an up vector for the model using HPS::Model::SetOrientation. The navigation cube orients along the model orientation.
https://docs.techsoft3d.com/hps/latest/build/api_ref/cppcs/class_h_p_s_1_1_model.html#a8e4eb59411e5864f22628799bf8e634ahtml
When just opening the model in sandbox:
...