can anyone teach me how to get device position from ground (display in screen) tutorial in unity

hi, I'm new to AR development. I need to create adaptive augmented reality apps that can calculate user height and display appropriate content to them. In this case, to determine the user is an adult or kids. I'm planning to create the apps using Unity. ,hi,

I'm new to AR development. I need to create adaptive augmented reality apps that can calculate user height and display appropriate content to them. In this case, to determine the user is an adult or kids. I'm planning to create the apps using Unity.