Approximation, prediction, or projection of a quantity based on experience and /or information available at the time, with the recognition that other pertinent facts are unclear or unknown. An estimate is almost the same as an educated guess, and the cheapest (and least accurate) type of modeling.
A building estimator is an individual that quantifies the materials, labour, and equipment needed.
An intelligent 3D architectural model incorporates all the 2D data, materials, drawings and documents which help the architectural designer to produce required plans, elevations, drawings, estimates and material details. He can apply various design alternatives to this 3D model and can instantly check their impact on the final output and cost. The result is a better design and efficient material utilization. The building model can also be rotated to produce additional views and perspectives.
3D visualization can give architects and clients a real idea of what the structure would look like, presenting precise dimensions and finely rendered structural information.