When working with a designer it may be helpful to have a rendered model of the proposed space.
Here is an example of a rendering for our client's roof top deck and the final project. In this rendered model, the client wanted to better understand the relationship of the volume within the space along with a few of the finishes. Renderings and models are excellent ways to communicate the design intent. They can be very basic to show volume or get super detailed to give a more realistic image, it's up to you as the client to decide how much time and money it is worth.
For more information on this amazing San Francisco project check out the Jackson St. Penthouse.