Design Development
It was decided that the initial idea looked too much like a castle and not enough like a cake, so the baton was passed to Disney Attractions Entertainment, where we picked up the project again and came up with several alternative ideas, including this one, which incorporates different kinds of candy stuck in the "frosting."  The pink color, although controversial, served to distinguish this decor package from the Castle's original blue and gray.
The Design Process
Cinderella's Castle Cake
Concept Sketches showing progression from Initial Concept through Design Development to Final Scale Drawings and Art Direction
Steps in the Process

Initial Consultation: listening to the
  client, determining scope

Brainstorming / Research: coming
  up with ideas

Rough Concept: sketches,  
  schematic diagrams, written

Choosing a Concept from among
  alternative roughs

Defining the Concept from client’s

Presentation Package: master plan,
  guest experience, storyboards, 
  logos, bird’s-eye rendering

Design Development: detailed
  design, scripting, technical plans,
  architectural drawings, scenic
  scope, merchandise, promotional

Art Direction: working drawings,
  supervision of fabricators and
  contractors, interior decoration, etc.
Projects vary in length, complexity, budget and scope, not to mention purpose, style, target audience and cultural context.  But the design process is pretty much the same for all of them. 
   The talented designers at Radical Concepts can jump in at any point in the project’s timeline,or start from the very beginning, even before the client knows what he wants.  In fact, the fewer creative decisions you’ve already made, the more we can help you with -- and you’ll be glad you asked us.

Initial Concept
Walt Disney Imagineering took to heart our idea of transforming Cinderella's Castle into a giant birthday cake for WDW's 25th Anniversary Celebration, and had us draw up a few color sketches of their version of the concept.
Unless otherwise indicated, all images copyright © Radical Concepts, Inc.
© Disney
Art Direction
Sometimes a client needs a full-color painting or a digitally altered photograph to visualize the project's final form.  But in this case, familiarity with the building made it unnecessary, so we concentrated on producing scale drawings and a detailed written Scenic Scope.  After climbing all over the Castle and poring over the original blueprints, we were able to determine exactly which faux candies would go where, and in what color pattern, as this drawing is meant to show.
Fabrication and Installation
This project involved two primary fabrication companies.  The Nassal Company in Orlando carved and colored the fiberglass candies and the icing located near the ground while custom balloon maker Aerostar in Sioux Falls, South Dakota, made the inflatable pieces, such as the candle spires and stacks of hard candy.  One of our challenges was to travel between the two companies and make sure the color treatment of the icing looked the same whether it was made of carved styrofoam or inflated nylon. The transformation was accomplished under cover of darkness, and remained in place for a full fifteen months.
© Disney
© Disney