How to create a cube in 2d view and scale it based on a point/anchor? Than visualize the cube in 3d.

I want to create a cube/wall in 2d view and change its scale from one side based on a pivot or anchor, after that see the cube in 3d view.

Here is a youtube link/example of what I want to achieve:

basically taking a room shape and manipulate its scale than view in 3d. The live demo is available here:

Do you mean inside the Editor?
Inside the Editor you could use the rect Transform.

if you mean in runtime you could write a script with set the Camera state to Orthographic than to Perspective. Thats Mesh derform, wich is difficult in Unity- but possible.