Hi!,
Here are exact steps
1) You will send us the package of 3D models
2) Exact technical description such as if the user will be able to walk through buildings in order to provide collider meshes (or we should create them) and etc. The goal is to define what you need.
3) We will provide fast prototype solution via Unity3D for you to approve the final solution, in order to be sure that we are developing what you are interested in.
4) We will develop the City Viewer on WebGL by setting the Camera, Plane on which buildings will be set and e.g collider meshes for not moving into the builds (this will be finally set during second step).
5) Any additional tasks such as UI, or Free view etc.
Kind Regards,
Tigran