Schedule generation is an important part of the construction planning process. The process of schedule generation is usually modified and carried out several time during the whole life of a construction project. Traditionally, construction planner uses the CPM-based network and bar charts to describe the schedule of a project. The whole process of schedule development depends on the experience and knowledge of construction planner to interpret the information from 2D CAD drawings. Such shortcomings of conventional CPM/bar chart schedules have spawned the development of 4D planning (3D CAD + schedule integration). 4D planning have been identified by many within the industry as a technology that provides an opportunity to improve an existing construction schedule by identifying inconsistencies and out-of sequence activities; reducing missing activities; and improving the ability to communicate construction plan information at an early stages of a construction project. 

The aim of this paper is to investigate the applicability and usefulness of implementing 4D planning in evaluating the feasibility of the schedules, such as to explore various schedule alternatives; cost of alternate construction sequence; identifying and resolving schedule conflicts through a real life case study. An action research methodology has been adopted. A 4D model of foundation work, structural steel, external skin work, internal brickwork and mechanical & electrical services has been developed for the case study. The developed 4D model was then evaluated by the planners to identify the issues and conflicts present within the planned schedule to avoid any time and cost related uncertainties. The feedback and suggestions provided by the project planner has been used to modify the original schedule. The modified schedule will then be used to update the 4D model on weekly basis and updated model was again reviewed by the planner to identify any inconsistencies in the schedule. The interactive review of 4D model has assisted the construction planner to discover two major conflicts in the schedule which were not discovered in the CPM-based Gantt chart. 

Through this real life case study it is anticipated that the outcome of this study will provide an evidence of how the interactive review of 4D can assist planners to save the time on the project. 
