The main thing is looking at the hardware that will be running the app (a mobile phone, VR headset, AR glasses, mobile VR gadget, etc.) and evaluating how much power a user needs to work with. Then, we also have to decide which models are primary (the focus of attention) and which will be located in the background. Precisely, this sheds light on the level of detail invested in each type and what scale/perspective is required for them.