Overview
Project managers can create a 4D simulation of the planned construction process by linking elements in the composite model to a timeline of project tasks. 4D simulations can have many construction process planning applications; for example, validating the planned sequence are construction operations and identifying any time-based clashes.
{slider Creating a 4D Simulation |closed}
By linking timelines of project tasks to model elements, we can create a complete 4D simulation of the construction process from the demolition phase through owner move-in. This simulation can be used to inform critical planning decisions about construction methods, resource allocation, activity sequencing, site space utilization, and so on.
The Navisworks® Manage TimeLiner tool enables project teams to:
- Manually enter information about project tasks.
- Import project schedules from a wide variety of project planning tools.
- Link elements in the composite model with tasks in the schedule.
- Simulate the schedule and see the effects on the model, including planned versus actual schedules.
- Export images and animations based on the results of the simulation.
TimeLiner automatically updates the simulation if the model or schedule changes and offers many options for creating customized simulations to support the needs of the project team.
Before linking the composite model to schedule tasks, it is helpful to group model elements and create selection and search sets that facilitate easy mapping; the importance of this point will be demonstrated in the tutorials. {slider Identifying Time-Based Clashes}
For complicated projects where the site space is constrained, project managers must carefully plan the sequence of operations to make sure that the demolition, permanent construction, and temporary construction activities can occur without creating conflicts. The vast number of moving parts and equipment involved in a construction project makes time-based clash testing incredibly valuable to project managers in their continuing effort to coordinate the trades, materials, and equipment that must coexist in the limited space available.
The ability to forecast and anticipate problems before they occur is essential for effective project management. When the cost of schedule delays or construction rework because of errors is considered, it is clear that project managers need to carefully plan and orchestrate construction operations down to the last detail, both in space and time.
Construction planning models can be created and integrated with the composite project model to consider the impact of temporary items, such as work packages, formwork, cranes, installations, and so on. The locations of these temporary items can be modeled and linked to the project timeline, so that their appearance and removal at particular project locations over specific periods of time can be verified and checked for potential time-based clashes.
By combining the functionality of the Autodesk® Navisworks® Manage TimeLiner and Clash Detective tools, project teams can perform time-based clash checks on the project and continue with this automated checking throughout the project lifetime. {/sliders}
Learning Objectives
After completing this lesson, you will be able to:
- Define selection and search sets to easily map model elements to the scheduled construction tasks.
- Assess the best method for mapping model elements to schedule tasks—either manually or by defining mapping rules.
- Identify problems in construction sequencing through 4D simulation.
- Understand the various methods available for saving and sharing a timeline simulation.
- Identify time-based clashes that temporary construction materials.
Tutorials
Creating a 4D Simulation
In this exercise, you will learn how to:
- Link a schedule file to the TimeLiner tool and generate the hierarchy of tasks.
- Create selection sets and search sets to facilitate linking model elements to the schedule tasks.
- Specify simulation settings and run a 4D simulation.
Figure 5.3.1 - Simulating the construction of foundation elements
- Open the downloaded .NWF file in Navisworks Manage.
- Continuing from the point where the tutorial left off, creating additional search and selection sets to select groups of model objects between Level 2 and the Roof level. Each set should contain the elements to be mapped to a specific task in the construction schedule.
- Use the TimeLiner tool to attach the sets of objects to their associated schedule tasks.
- Run a 4D simulation of the construction schedule. Modify the playback duration and interval size to achieve the desired visual effect for effectively sharing the simulation with others.
Figure 5.3.2 - 4D simulation of the complete building model
Identifying Time-Based Clashes
In this exercise, you will learn how to:
- Reveal a time-based clash by linking a clash test to the project schedule.
- Add schedule tasks to accurately reflect the existence of temporary construction objects, and attach model geometry to that task.
- Run a time-based clash test to confirm the elimination of the time-based clash.
- Run a 4D simulation that includes the appearance and disappearance of temporary object to the project.
Figure 5.3.3 - Clash testing the materials lift against the architectural and structural model elements
- Open the downloaded file in Navisworks Manage.
- Use the project schedule to determine the date by which the material lift must be removed in order to avoid interfering with the installation of the building stair.
- Modify the schedule task linked to the materials lift so that it reflects the required installation and removal dates.
- Perform a time-based clash test between the Construction_Equipment and the Architectural_Shell models to confirm that a clash no longer exists between the materials lift and the stair. Be sure to link to the TimeLiner when you run this test in the Clash Detective tool.
Figure 5.3.4 - Adjusting the start and finish dates of the task associated with the temporary materials lift
Assessment
Creating a 4D Simulation
- Who are the project team members that might be most interested in seeing the 4D simulation?
Team members responsible for planning and executing construction operations are most interested in the 4D simulation results. For example, the construction superintendent, contractors, and subcontractors.
- Can you automatically map schedule tasks to search or selection sets in the composite model?
If you carefully match the names between the sets and the schedule tasks, automatic mapping is possible. The TimeLiner rules tab includes an option to Map TimeLiner Tasks from Column Name to Selection Sets with the Same Name. Using this rule, all items associated with a search set will be attached to the task of the same name.
- What types of projects would receive the greatest benefit from creating 4D simulations to illustrate the construction process to the general public or governing officials?
Busy downtown construction sites where commercial and residential property owners will feel the impacts of the construction process on their daily routines are good candidates for 4D simulation. Also, transportation projects where major detours will be needed during the course of completing the project.
Identifying Time-Based Clashes
- How do you model dynamic representations of temporary items—for example, work packages, ships, cranes, and other installation equipment? Can you perform a clash test that takes these moving work packages into account?
You could use the Animator window to create animation scenes with these objects, so that they will be moving around a project site, change their size, and so forth.
Since these moving objects could collide, “soft clashing” enables the automated checking of this. In a soft clash test, at each step of a scene sequence, Clash Detective checks to see if a clash has occurred. If it has, the time of the clash is logged, along with the event that caused the clash.
Key Terms
Key Term | Definition |
Tasks | Activities that appear in the project schedule. These activities can include construction, demolition, or temporary operations. |
4D Simulation | A simulation of a construction process that maps model elements to schedule tasks, adding the fourth dimension of time to a 3D model. |
Time-based Clash | A clash occurring when two static model elements occupy the same space at a specific time in the project schedule. |
Soft Clash | A clash occurring when two moving objects collide. |
Time-based Soft Clash | A clash occurring when the appearance or disappearance of static objects obstructs the movement of animated objects on the site. |