The move to a BIM-centric design methodology as part of an integrated project delivery (IPD) strategy creates the need for a new responsibility and role within the organization: the model manager. Whether a full-time dedicated position or a secondary assignment to a manager with other responsibilities, the role is essential for facilitating model integration and maximizing the model’s utility to all of the parties across the project organization.
The model manager typically creates a Model Coordination Plan that establishes standards and lays out a framework for how the pieces that will be integrated into a composite project model will be created, shared, transferred, documented, and published. Standards and best practices must be established regarding software preferences, naming conventions, file transfer methods, and file sharing and editing permissions.
While model viewing software solutions, such as Autodesk® Navisworks® products, help make it relatively easy to integrate models from a wide variety of sources and in many file formats, each file format option has advantages and disadvantages. An experienced model manager must become familiar with the implications of these format differences on downstream workflow and recommend preferred choices.
Very few project teams work on a single software platform that all members can share. It is much more common that project team members each work with their own preferred software tools, and the outputs of these tools must be integrated to create a composite project model. For these teams, software that can aggregate many disparate models into a single analysis and viewing environment is essential.
In this lesson, students will explore the model importing capabilities of Autodesk®Navisworks® Manage software to create composite models that can be viewed and explored.
Navisworks® Manage has its own native file formats (.nwd, .nwf, .nwc), but it can also import models created by many other modeling tools using common BIM and CAD file formats, such as the ones listed in the table below.
Creating a Composite Model
To prepare a model for review by the entire multidisciplinary team, it is essential to unite the models prepared by each discipline into one shared reviewing environment, such as Navisworks® Manage.
Many different types of models can be integrated into the composite model, depending on the specific needs and the nature of the project. For example, these might include site, existing utilities, existing buildings, roadwork, temporary structures (formwork or scaffolding), finished structure, architectural shell, MEP, and so on.
Creating a composite model requires an understanding of the available 3D modeling applications and their associated export and import functionalities. To aggregate the models in Navisworks® Manage, they must be exported to the native NWC file format or one of the other compatible 3D formats, such as DWG or IFC.Each file format has its own strengths and limitations. So the project team should create and deploy a Model Coordination Plan within the design and construction team to avoid potential file and data compatibility problems.
Figure 5.1.1 - Navisworks Manage imports models using many common 3D file formats
Exploring a Composite Model
Having created a composite model that integrates models from the various design team participants, the team can now explore and interact with the unified composite model. Viewpoints of interest can be saved for later review, analysis, and presentation. These viewpoints might focus on finite issues requiring resolution, or, might present big picture views that show the interaction of building systems.
To create special scene views that more clearly communicate the design intent, model managers can:
- Use different camera positions.
- Hide or require selected elements or categories of elements.
- Change color and transparency overrides of individual elements or categories of elements to emphasize or diminish their appearance.
Viewpoints—snapshots of the model as it is displayed in the scene view—can be used for more than just saving a specific view of the model. Model reviewers can add annotations with redlines and comments that create a design review audit trail. When viewpoints are recalled, the redlines and comments saved with the viewpoint also appear.Viewpoints can also save the color and transparency overrides, hidden items, section planes, navigation speeds, and modes that best convey and communicate the issues discovered during the model review. This guarantees that when someone reviews the viewpoints, they will see a view model that displays the information exactly as you intended.
Defining Sets of Model Elements
BIM models can contain detailed information that describes the properties and parameters of the model elements in addition to the geometry that enables the models to be utilized throughout the full lifecycle of the building. Navisworks® Manage enables reviewers to interrogate and use this information for many design, construction, and operational purposes without the need for the originating design software.
To prepare for the different types analyses that will run at various project stages, it is typically useful to create “intelligent” groups or sets of objects. These can be created as:
- Search sets—specified by finding items based on search criteria to select items having a common property or combination of properties.
- Selection sets—specified by selecting items directly in a scene view or in the element selection tree and manually assigning them to a set.
The most efficient method depends on how elements are organized by name or in the selection tree hierarchy. Generally, if search sets can be used, they offer the quickest method and can be saved and exported to other projects. While the method used to create sets can differ, the sets defined can be used interchangeably in analysis.
Sets can be used to facilitate many type of analysis, for example, to:
- Perform clash detections between model objects.
- Link model elements to schedule tasks.