However, this 4D simulation does not help to create better schedules (except for catching obvious issues, such as building 4th floor before 3rd floor) or to control the project better. It is powerful as a visualization tool but if the plan is not optimized, it is of little value because it will not be followed anyway. Gluing traditional CPM schedules to design models works for demonstrations, but is too time-consuming to be useful in real production - any changes will have to be manually updated, and everyone knows that traditional CPM schedules change monthly and design is continuously evolving.
Owners should not be content with pretty movies but should pay special attention to the intelligence behind the schedule - quantities, resources, means and methods. This information content is a better predictor of whether or not a General Contractor can deliver rather than the ability of the General Contractor to create a snapshot simulation movie. Owners should require that durations are justified with quantities and productivity rates. Otherwise, there cannot be constructive arguments, because within reasonable constraints, duration is a choice and a function of quantity and resources. Owners can be satisfied with the schedule only after all optimization opportunities have been exhausted.
For us at Vico, 4D means much more than just a simulation. 3D models are powerful tools to calculate quantities that are necessary to drive the schedules. Construction is repetitive work in locations. These locations can be visually identified in 3D models and the resulting location-based quantities can be used to calculate accurate durations for each location. This automated duration calculation enables crew optimization to achieve continuous work-flow and reduced waste in the process. This optimization can reduce durations by 10% without increasing resources. 20% reduction is achievable if strong location-based controlling methods are also adopted.
Because everything is linked to the model, all the assumptions are easily verifiable and can be graphically demonstrated. This 4D makes is possible for a layman to understand why the duration should be 10 days instead of 5 days and why the welding is the bottleneck trade which defines the pace of other activities. The model is used to generate the schedule instead of just linking a schedule to a model - this makes updates easy because any design update will update the quantities which will automatically update the schedule. A 4D simulation movie is generated as a by-product, the intelligence is what really matters in a true 4D schedule.
For more information on model-based scheduling, please utilize the following resources:
Webinar: Introduction to LBS Manager
Video: 5D BIM for Dummies
Webpage: What Is 4D BIM?
Webpage: What Is Flowline Theory?
We also offer a step-by-step guide to our 5D virtual construction workflow with video tutorials. These videos are just 2-5 minutes in length, but illustrate how to use a particular piece of functionality. You can access the video library index and view just what you need, or download the complete set of training videos. We have training levels for Estimators, Schedulers, Supers, and anyone who does CM Reporting.
Perhaps the best example of an animation derived to show the schedule can be found in the Hensel Phelps Denver Justice Center webinar. Scroll to the end of the presentation to watch the animated schedule as compared to the webcam images from the site. This shows the power of optimizing the schedule AND controlling it on-site.