Let us now move on to look at the key NavisWorks tools in more detail and see how its capabilities compare with those of the other applications in the 3D publishing and review genre.

Roamer: The NavisWorks Hub

You start in NavisWorks with the core application, Roamer. Here, you can open a 3D file in a variety of file formats including DWG, DXF, DGN, 3DS, IGES, and so on. Once a file is open, other files can be appended to it, allowing a complex scene to be built from a number of smaller models in the same or different file formats. If required, the scale, rotation, and origin of an appended model can be changed to synchronize it with the other models. The combined set of models can be published as a single highly-compressed NavisWorks .nwd file using the NavisWorks Publisher plugin, which can then be viewed with the free NavisWorks Freedom viewer. The files can also simply be saved an .nwf file. No geometry is saved in this format, but a list of appended files, along with their path relative to the .nwf file is saved, along with any overrides, color changes, comments, redlines, viewpoints, or other NavisWorks specific information.

Once the file or files have been brought into Roamer, their 3D content can be viewed and navigated in a variety of ways. NavisWorks guarantees interactive navigation of virtually any size model with a guaranteed frame rate, and I found this to be true. With eight different kinds of navigation modes-Zoom, Pan, Orbit, Examine, Look Around, Turntable, Walk, and Fly-the model can be easily seen from any desired angle. Complementing these modes is another set of navigation tools for aligning the current view along the X, Y, or Z axes, viewing the whole model or a selected element, setting the view to perspective or orthographic mode, and some other functions. A tilt slider is also available for controlling the tilt angle of the view, particularly useful in the Walk mode for looking up and down. Plan and section thumbnail views are available with a triangular marker representing the current viewpoint; this marker can be dragged to quickly relocate the camera to a different position within the model. Critical views can be saved for easy access in a Viewpoints palette, which also includes any saved views from the original file(s). In addition, preset views such as left, right, top, and so on are readily available as menu options.

In addition to navigation, NavisWorks provides an extensive set of options for selecting individual elements or element groups within the model. A Selection Tree palette provides a hierarchical view of the structure of the model, as defined by the CAD application in which the model was created. Using this palette, items can be selected at different levels: an individual item of geometry, a group such as a block or cell, a layer or level, or a whole model. Figure shows an example of this hierarchical structure in the Selection Tree palette with the "restaurant seating" layer selected; all the corresponding items in the model are selected, as indicated by the blue selection color in the main graphics window. An option to search and select items by properties such as material, geometry, and so on is also available. Selected groups of items can be stored in the form of selection sets for easy retrieval later.

What can you do with selected items? For a start, you can hide them or hide all the other non-selected items. This is useful for a detailed look at the items themselves or at the objects they might be hiding.  shows how this capability is used for temporarily hiding a roof element in order to examine its supporting structure more closely. This is where the capabilities of NavisWorks start to extend from navigation alone to design review as well. Additionally for selected items, you can temporarily override their color and transparency attributes to explore material alternatives, as well as any hyperlinks that were attached to them in the original authoring applications. These overrides are saved into the .nwf files for future use, but can be reset to their original values at any time.

Other design review capabilities include the ability to attach comments and new hyperlinks to selected items, and add redlines to saved viewports. These are also saved in the .nwf file and can be recalled when needed. Additional utilities in Roamer include a set of tools for measuring distances, areas, and angles in the model; smart tags that display pop-up information about an item by moving over it without having to select it; sectioning tools that allow up to 6 sectional cuts to be made in any plane while still being able to navigate around the scene, providing the ability to see inside models without hiding any item; and a choice of four interactive lighting modes and four different rendering modes. Animations can be created in Roamer in two ways: either by simply recording a real time walk through, or by assembling specific viewpoints that are then interpolated into an animation.

In addition to publishing to .nwd or saving to .nwf, NavisWorks Roamer has a few other output options. The current view can be printed or exported to one of three file formats: Windows BMP, JPEG, and Piranesi Epix. The option to export an animation as an AVI file is also available.

Presenter, Clash Detective, and Timeliner

As mentioned earlier, the other NavisWorks tools are available as separate plug-in modules for Roamer. They do not need to be installed separately, but simply require separate license codes that can be entered during the NavisWorks installation. If NavisWorks is to be used to create photorealistic output, the Presenter tool will be required. When installed, it is available as a menu option within Roamer and can be opened as a tool palette, as shown . From this palette, different materials, lights, and effects available in accompanying libraries can be dragged and dropped into the model. Textures automatically size themselves appropriately according to the scale of the model when they are applied to elements; if adjustments are needed, an option to edit them in texture space is also available. A Render button in the Presenter palette renders the scene photorealistically, complete with lights, shadows, and textures; the resulting image has additional export options such as TIFF and Targa, in addition to the basic options of Roamer. In addition to photorealistic output, Presenter can also produce renderings in a variety of sketch styles that are available under the Effects tab, along with a choice of background options and foreground effects such as fog and snow.

The most expensive application in the NavisWorks suite is Clash Detective, which allows the model to be checked for geometric interferences. From an AEC perspective, this can be used to check, for instance, a structural model and an HVAC model of the same building and detect and fix errors such as a duct passing through a beam. It is critical to fix such errors at design time rather than leave them unchecked till they are detected at the construction site, where they are so much more expensive to fix. However, since Clash Detective has no knowledge of building components as such and only works on the basis of geometry, it will be useful only when the building components in the original CAD applications are clearly differentiated into different categories such as walls, beams, columns, ducts, and so on by using layers, blocks, materials, and other grouping mechanisms.

 shows Clash Detective in action to detect clashes between the outer skin and supporting truss of the same model. After selecting the elements or element groups that are to be checked against each other, specifying a tolerance value, and setting options for clash type and interference method, the Clash test can be run. The results window lists all the detected clashes, and allows each instance to be inspected more closely in the graphics window by using the Auto Zoom and Dim Other options. Details of the clashed items can be reviewed for every clash. Clashes can be set to a different Status depending upon whether they are still active, approved, or resolved. And finally, reports in various formats, including HTML, can be generated that capture the results of one or more clash tests.

The latest entrant to the NavisWorks suite is TimeLiner, which further extends the capabilities of the model to perform 4D construction simulation. The TimeLiner plug-in within Roamer provides direct links to popular project scheduling applications such as Primavera P3 and Microsoft Project, and can also work with task schedules in the common MPX format created by other applications such as Primavera SureTrak. All the individual tasks from the linked task schedule file can be imported, associated with a task type such as Construct, Demolish, or Temporary, and finally, assigned the model items that need to be associated with them. Items can be selected and manually attached to tasks, or if the task names correspond with the names of layers, selection sets, or the items themselves, the assignment can be made automatically using the appropriate rule. After all the items in the model have been assigned to tasks, the display settings for the simulation can be defined, and the simulation can be played.