Idea for a project - Room Furniture Configurator


I have a project to do “Room Furniture Configurator” so people can pick up models (furniture pieces) from a left menu and appear on scene. Normally it has to be placed in the middle of the stage but if there is another model there it has to go to the right or left where it finds a place.

Do you have any idea how I could do that?

++ How can i make a right panel with scene and left panel with a menu? I know with 2d screen but i need like scene 70% width and menu 30% width of a screen.

Thank you