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Navisworks is Not Just for Clash Detection

INtroDuCtIoNAs soon as one hears the term Navisworks, they automatically think clash detection. That is really a shame because there are several other uses of the product that provide great value to the user. The

purpose of this article is to provide an overview of the uses and benefits of Navisworks, and how one can incorporate Navisworks into the production workflow. In simple terms, Navisworks is a software package used for reviewing and communicating infor-mation about a 3D model. Pretty much any 3D file format can be read into Navisworks and multiple models can be combined into one file. As a model develops over the course of design, it can be refreshed in the same Navisworks file, negating the need to re-as-semble models from scratch each time Navisworks is used.

NavIsworks IN your ProDuCtIoN workflowIn a typical situation a user will create a 3D model. This may be a model created in Revit, a model created in AutoCAD, a model created in Sketchup, or perhaps in 3DS Max. You can also bring in your structural analysis model. In order to get the model into Navisworks you can either just read the file in, if it is a file format that Navisworks reads natively, or you will need to export the file in a proper format. For example, if you are using Revit, you will need to export the file since Navisworks does not currently read native .rvt files. Your typical export format options would be either as a dwg file, or as an nwc file. The primary difference between these two formats is the way the model information is categorized. A dwg export will categorize the model in layers, whereas the nwc file will categorize per project level. See Figures 1 and 2.

When exporting as a dwg file from Revit, remember to select ACIS Solids in the export options if you want to be able to select discrete model elements.

You may also have project information in 3D models other than Revit. When we design our retractable roofs, we often detail complex structural steel connections in TEKLA Structures. We will export these connections from TEKLA in IFC format and then bring them into Navisworks and combine them with our primary structural model in order to view all model information at once. This process is also used to bring in the geometrically complex parts of a project that may have been modeled in 3DS Max or similar programs. The terrain as shown in Figures 1 and 2 was brought in from Google Earth to Sketchup, and then appended to the Navisworks model.

Another excellent use of Navisworks is to compare the BIM and structural analysis models. Unfortunately in most cases our BIM model and analysis models are separate models, but being able to bring them both into a single Navisworks file allows for a quick review of the models for missing or uncoordinated geometry.

Before we decide what to do with our model, there is one more step I like to take, and that is make the model “look nice.” As you can see in Figure 1, a dwg import will present you with the gaudy AutoCAD color palette. An nwc import isn’t much better, just duller (see Figure 2). So go ahead and change the colors. Make the colors distinct, so you can visually identify groups of elements easily, and of course make them pleasant to look at. You can also take it a step further and create a custom material palette, as shown in Figure 3. The same model shown in Figures 1 and 2 is shown in Figure 4 with the custom palette applied.

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Figure 1 - Model Imported asa dwg File

by: Joseph Ales

Figure 2 - Model Imported as a nwc file

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Now that we have our model in Navisworks, what do we do with it?

walk-through CoorDINatIoNWhen I go out to a job site, my primary task is to walk through the building and identify anything that is wrong, and make sure it is being built as I have shown on my documents (or should I now say model!) Wouldn’t it be nice to do the same thing before it is built, and identify problems before they occur in the field? Well, Navisworks is the perfect tool to perform this task. Think of it as creating your own virtual punch list. Of course, you cannot physically walk through the building (since it hasn’t been built) but Navisworks will provide you with an Avatar to walk through the building for you. The Avatar can walk up and down stairs (or fly if you want), bump his head if there is a beam in the way, and look around at anything you want. When you come to something in the model that is not right, you can document the issue in a couple of different ways.

1. Save the view as a viewpoint and title the viewpoint with a description of the problem. As you walk through the model you will slowly build up a collection of views that illustrate coordination issues. You can also use the Navisworks red-line tools to markup these problems. This set of viewpoints can then be exported into a report or saved in an nwd file that can be shared with others.

2. Take a snapshot of the view using Design Review and mark up the problem that way. Design Review has superior markup tools compared to Navisworks and it may be more

convenient to share marked up dwf files than a viewpoint re-port or an nwd file.

So if you don’t want to run clash detection, and you want to take a tour of your building, walk-through coordination is your answer.

vIsualIzatIoNNot everyone is a master of 3D Studio Max, but everyone would like to produce nice rendered images of their model, or even pro-duce a fly-through video. Fortunately Navisworks has made it fairly easily to do both. In order to render an image you will need to use the Presenter module. Navisworks comes with a whole host of built in materials, as shown in Figure 6. Since I am normally dealing with concrete and steel materials, I don’t want everything gray. I apply different colors to a basic concrete or steel material in order to differentiate various components. For example, my con-crete and steel beams are red, my slabs are gray, and my foundations are green. Our purpose in rendering is not to create a photo-realistic image but to produce a nice image that communicates

design information to the viewers. Since you have already created your custom material palette (see Figure 3) it is easy to apply the ma-terials to your model. The tricky part with the rendering is to apply the lighting properly. This will take some trial and error on your part to find out what works best. The image in Figure 7 was pro-duced with the custom material palette and a spot light applied.

Figure 3 - Custom Material Palette

Figure 4 - Custom Material Pallette Applied

Figure 5 - Coordination Items Documented Through Viewpoints

Figure 6 - Built in Materials

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Creating a video is pretty straight-for-ward. Make sure you are in Walk mode, select the Animation tab, and press Record. Now start walking. Just like a Macro Re-corder, Navisworks will record the ac-tions of your Avatar walking through the project. When you are finished, press Stop. The animation is saved along with any other Viewpoints you have and you can play it back whenever you need to. Your

animations can be exported as a video, or they can be saved as part of any nwd files you create. It is usually best to share your animations using an nwd file as the quality of the video is a bit better and the file size is smaller. Exported videos can get very large, very fast, if you want something of good quality and larger than a mobile phone screen.

CoNstruCtIoN sequeNCINgThe constructability of a project is an important consideration in the design process. It is generally not a good idea to design some-thing that cannot be built. By using Timeliner in Navisworks, very simple to very complicated construction sequencing visual-izations can be created. All you need is a construction schedule, and some persistence and patience in applying this schedule to the model.

The construction schedule can be entered either manually in Navisworks, or it can be imported from a scheduling program. If you are not a contractor, then you will probably be using Mi-crosoft Project as your scheduling software. I recommend that you link the schedule in, as it will be faster and easier to create in the scheduling software. A new feature of Navisworks 2011 is the ability to view a Gantt chart of the schedule (shown in Figure 8), which allows for easier visualization of the construction se-quence. The tasks entered into your schedule will then need to be

applied to the relevant elements in the model. For example, if the task was “Form and Pour Foundations East of Grid C,” then you would select all of these foundations in the model and apply the task to these foundations.

You have several options for setting the timing and appearance of the model elements as well. Using Task Type, elements can either be constructed, which means they will appear at the time they are built; elements can be demolished, which means they will disappear; and elements that are temporary, such as construction equipment. The appearance of the elements can also set through the Configure Tab, as shown in Figure 9. This is about commu-nicating information, and Navisworks once again provides plenty of tools to accomplish the task.

We are just scratching the surface of what Timeliner can do, but a little bit of investment in time to learn this tool can pay off as you show your client some real-world aspects of building their project. The following tips will make your job a bit easier.

1. Group your elements together in Navisworks, rather than scheduling them one at a time, as it can get quite complicated and time-consuming to apply the schedule as the number of model elements increases. See Figure 10 below.

2. Make sure that you model in sufficient detail in order to map to the likely tasks in the schedule. For example, if you model your columns from foundation to roof in Revit, rather than level to level, you will need to re-model in order to capture the proper sequencing of the columns.

3. Run through the sequencing process a few times, as it is easy to miss some elements or assign them to the wrong task. Your finished construction sequence will be saved as part of your file, and you can export it as a video to share with oth-ers.

4. Under Settings, set the time of your simulation to an appro-priate length. Set it too fast, and you won’t see anything. Set it too long, and it will get a bit tedious to watch. Again, some trial and error will be required.

Figure 7 - Rendered Image

Figure 8 - Gantt Chart

Figure 9 - Configuration Options in Timeliner

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CoNClusIoNI hope I have shown you that Navisworks is not just for clash detection. Do not limit the use of Navisworks to just the BIM gurus in your office. Make it part of your normal production pro-

cess, and in combination with Revit and Design Review, it will allow you to work more efficiently, produce better quality docu-ments (and models), and give your firm a competitive edge in the marketplace. And I have not even mentioned Naviswork’s new Animation feature, which allows you to animate objects, cam-eras, and section planes. Thinking outside of the box is always a good thing but it is especially important in today’s economy when it is vital to set yourself apart from the competition. By using Navisworks to its full potential, you are showing your clients the added value you will bring to their projects.

Joe Ales is a Principal and Managing Director for the Los Angeles office of Walter P Moore, a consult-ing engineering firm based in Houston, Texas. He is part of the structural engineering service group of Walter P Moore and is chair of its BIM Implemen-tation Task Force. He is also active in the BIM technical community, serving as Vice-chair of the Joint SEI – CASE Committee on Building Infor-mation Modeling for the Structural Engineering Institute.

Figure 10 - Screenshot from Timeliner Simulation