Build Unity3D Game prototype

I am looking for a developer to make a prototype application for creating fun, interactive objects. I will include reasonable detailed mockups during the development process. The application must include the following -A generated 3d terrain similar to or derived from this: [login to view URL] -Ability to zoom in/out on and pan across the terrain -Assets for 3 different buttons in the main user interface -Ability to read a JSON file of 3d OBJ models, and display them in a selection box with a search by name -Ability to drag those objects into the world -Ability to select and display variations of the objects dropped into the world through another popup window. These variations will be mapped into a 2-d space by a Hilbert curve, and will be loaded in real time from OBJ files over the network. -An interface for the user to configure parent/child relationships with the objects and attach child objects using fixed connections, hinge joints, spring joints and axles. These joints should be configured using the built in Unity physics capabilities. -Ability to right click/long press an object in the world to duplicate, scale, or select other variations. The prototype should be built in Unity 3d with C#. The developer should use Github to regularly check in code and build to a Unity desktop target to start.