Navisworks Takes OffDecember 24th, 2013Autodesk Navisworks 2014 takes off model quantities and allows for revisions. In this article, well delve into Navisworks catalogs and explore how to take off model quantities and how to take off items that are not modeled.QuantificationThe quantification tool is broken out into multiple panes. The Navigation pane shows items and the resources associated with them. The rollup pane gives header-level information and the takeoff pane gives item-level information.

Figure 1: Quantification moduleYou can think of items as assemblies composed of resources. Resources can be customized to calculate quantities in items. The takeoff pane enumerates the quantities of each object taken off in the items resources. The sum of the amounts is listed in the rollup pane.Exploring CatalogsThere are two main catalogs: Resource catalog and Item Catalog. The Resource catalog should contain each item type you wish to take off. For example, if you are taking off a footing, you will want to take off concrete, rebar, and form work. This means you will need a resource for each.It is recommended to create folders in the resource catalog for each type of resource. For example, create a folder for concrete, metals, and wood. In each folder create the respective resource.When creating a resource you have the opportunity to modify the formulas used for calculation. Modify the formulas for each resource until they calculate to your specifications.Once you have created resources, you can create your items. For footings, create an item and name it by footing typefor example, Footing F8. Right-click the item and select the items you wish to use. Hold ctrl down to select multiple items and select the Use in Item button. The resources are now associated with the item.If you update a formula in the resource catalog, the change will propagate to each item that contains the resource. If you only want to change the resource in one item, you can modify the formula in the item catalog to change only the associated item.Model Quantity TakeoffBuilding information models vary in their diversity and complexity. Some models have astounding geometry; other models have poor geometry but are rich in data. When considering using Navisworks for model quantity takeoff, you are most interested in models that are rich in metadata.Navisworks will only take off model geometry when the model has metadata associated with it. This is important to keep in mind when reviewing dwg files and other file types that may not have quantity data associated with them.To take off model geometry, select the geometry you wish to take off. This can be accomplished in a variety of ways. A sustainable method would be to create a search set for model groups. For example, you might create a search set for footings, foundations, walls, doors, and so on. An alternative method that is often employed is the use of the Select Same tool, a great tool to use when taking off a similar object. For example, when taking off a particular footing, follow the steps listed below. Select the footing in the scene view Click the Select Same tool Select a common componentusually name or type is used Click the Model Takeoff button in the Quantification window

Figure 2: Select Same toolOnce the model is taken off, it appears in the rollup window and the quantification window. The geometry that was taken off will change in color in the scene view. You can toggle the visibility setting of items that have been taken off in the scene view by using the Hide Takeoff Show Takeoff tools. These tools make it easy to identify items that have not been taken off.Following a workflow of using the Select Same tool to select similar groups of geometry, the Model Takeoff tool to associate geometry with a takeoff item, and the Hide Takeoff items, you will be able to quickly take off all the quantities in your model. These quantities can be exported to an XML or Excel file.Model RevisionsIt is the nature of design and construction to have item quantities that are updated during the design and construction cycles. The Quantification module in Navisworks allows you to identify the changes to the quantities that you have taken off when a new version of the model is analyzed.An item can be updated by a new model quantity, a deletion in the new model version, or by a change in the formula of a resource. Each change will be listed in the status column of the takeoff pane. If there is new geometry in a revision of the model, it will have to be associated with an item for quantity calculations. You can detect new items by selecting the Hide Takeoff tool in the quantification window.

Figure 3: Item statusYou can review the changes to the quantities when there is an override or change by hovering your mouse over the affected cell. A fly out window will appear and display the old and new values of the quantities. You can then accept or reject the change. You can accept all the changes at once by selecting multiple rows in the takeoff pane and clicking the Update Selected by the Model. This will update your quantities to the new values taken off in the model revision. You could also reject all the changes by selecting the rows in the takeoff pane you wish to reject and selecting Remove Override from Selected. Using these methods you can manage the changes to the quantities during model revisions.Model ConsiderationsWhen performing model takeoffs, remember to ensure you are capturing the geometry you are interested in and not any duplicate geometry. It is not rare to find walls stacked on walls, walls used for geometry not meant for walls, and other model cheats. It is important to understand the model you have been given in order to properly obtain quantities.The model review process is key to ensuring you take off each element properly and ignore superfluous elements. It is also important to understand the nature of the elements you are taking off. For example, if you are taking off wall surface area from a Revit model, you are actually taking off net surface area. This means that any voids created by windows, doors, and other families will not be included in the surface area of the wall.Working with models can enhance your ability to quickly and accurately take off a project. A workflow can be established that allows you to review changes to geometry and persist quantity changes for pricing.

Quantification in NavisworksThis year's release of Navisworks has a feature that we think will change the way you work and bring intelligence to your Information packed models. Model based quantification isn't new, but combining it with the ability to combine Building Information Models from multiple file formats, take quantities directly from the Building Information Model, then run change analysis as the model changes we think is an important part of streamlining this generally time consuming and laborious process. In a short series of posts we'll explain what Quantification in Navisworks is and how to set it up, how to take off from your Building Information Model, and how to analyze changes when new iterations of the model come in. Navisworks is already used to bring together different disciplines into a single federated model. Once you have this you can take off elements of the model to constructible Items, which may contain Resources such as materials, or preliminaries, this will then combine the quantity data into a reporting format which can be exported into a spreadsheet or an API connection can be built for use in an estimating system so you can then start looking to cost the project directly from the Building Information Model. When changes take place in the model, Change Analysis can be run to ensure you have the latest correct quantities and can quickly find any new or deleted items from your takeoff. This brings the world of BIM to a new group of people who may never have had access to more than paper drawings or a 2D plan of the model and been disconnected from the process of modifications and refinements of the design.

Out of the box the 2014 release of Navisworks is set up to support quantities from Revit and DWF files; these would include Length, Width, Thickness, Height, Perimeter, Area, Volume and Weight if these are available in the properties, as well as counts of the items taken off. These properties are already in your models, in this example the Volume, Area and Length can be seen in the Element tab of the Properties window.

You can add resources to items, to build up a picture of the quantities of materials or labor of an item and use formulas to calculate figures based on properties. For example, this image shows the walls in the project are made up of several components and the relevant quantities are calculated based on the Area of the wall.

You can then export out these quantities to an Excel spreadsheet which you can then use in estimating software. When there are changes to the model you can run Change Analysis to see what has changed and how, with callouts detailing the change to allow you to verify that the change is an expected one.

Over the coming weeks there'll be a few posts to talk you through how to setup catalogs, perform takeoff, and export your quantities as well as some more advanced posts about bringing through additional quantities.Using Catalogues in Navisworks QuantificationIn the last blog post about Quantification in Navisworks we talked about the rough workflow of quantifying objects in Navisworks. In this blog we'll talk about the first step, building a catalog to classify your objects. This will be how you group Items, say all of your cavity walls, do they come under a superstructure classification, a masonry classification, a ground floor and second floor classification, a combination of the above, or a standard classification system your company or country uses. And this wall won't just be a solid block as it would be displayed in your authoring package; it's made up Resources of facing bricks, concrete blocks, insulation, wall ties and mortar, you may even want to account for the labor involved in building this wall. So this takes us to the Item Catalog and Resource Catalog windows, if these aren't displayed in the view you are in you can bring them up by going to View > Windows > and selecting their checkboxes. I find having the Quantification Workbook, Resource Catalog, Item Catalog and Find Items windows all on the same panel the easiest way to work, feel free to change this by using Navisworks Workspaces.

Project setup In the Quantification Workbook once you have a project loaded (I'd suggest if you don't have one handy, export out the basic sample project as an NWC from Revit 2014), go to Project Setup, this wizard allows you to select a predefined catalog, we supply three out of the box, or to select your own catalog in the Navisworks format, for today we'll just cover adding to an existing catalog, but we'll cover custom catalogs in another blog. If you select the "CSI-16" catalog and continue, select your units, I'll select Metric but if you're in the USA feel free to select Imperial, you then get the option to select which units apply to which measurement, for example you may have all heights in Meters but all Thicknesses in Millimeters, I'll just leave it as the default.

Item Catalog You will then be presented with a list of categories which parts of a building or infrastructure may fall under. Go to the Item Catalog tab and we can explore some more. If you Select a category or as we call them, Groups you will see that you can edit the name, Work Breakdown Structure (WBS) and Description to provide additional guidance. The WBS code can be letters and/or numbers and makes more sense when you build up the catalog to have groups within groups. What shows as 01 below, may be part of a structured way to find an item, for example 03.02.06.01 may refer to a cast in place concrete pile of a particular grade.

For the purposes of this example we're going to create a group named Cavity Walls in Masonry, and add a specific Brick on CMU 100mm Insulation Item in that group then add resources with formulas to that item to calculate the correct values.

Start off by selecting Masonry then clicking New Group and giving this the name 'Cavity Wall', you can then add a description and change the WBS if required. Then click New Item and name this 'Brick on CMU 100mm Insulation', you can again change WBS and the Description, but now you also have the ability to modify the object appearance once an item has been taken off, and modify how the values are calculated. You can add formulas at this Item level to apply to all quantities from the model, for example you may want to take the weight value of a steel structural beam and add a flat 5% on top of this value to account for fixtures, basic mathematical functions from Excel are support to add conditions to these formulas, I'll publish more detail about this in the future. For now we will just change the PrimaryQuantity, this can be used to select the main unit used to measure that item making it easier to view the relevant quantity, I have set this wall to use Area, in Square Meters.

Resource Catalog We will now add Resources in the Resource Catalog. Using the same procedure of creating Groups and this time Resources Add two folders, Masonry and Insulation, and populate them with Bricks, Concrete Blocks, Wall ties, Mortar and 100mm Insulation as below.

We can now go into the Resources and modify some of the formulas to get the right property for each resource. Let's start with bricks, typically you would want a total count of bricks which can be calculated using the Area property of the wall, so we know that there would be 60 bricks per square meter so we have changed the Count Value to "=ModelArea*60" and changed the Primary Quantity to Count and a unit of Each.

For Concrete blocks I have done the same but the Count value is "=ModelArea*10" instead and on Wall Ties the Count value is "=ModelArea*2.5". In Mortar we are looking for a Weight in Metric Tonnes, So we will multiply the Area by 66 and select the PrimaryQuantity as Weight, but because we want this in Tonnes rather than Kilograms we will multiply by 1000, this could be worked out as how many bags are required, or lorryloads, whichever is the easiest to work in.

For Insulation, we will simply take Area in Square Meters as the PrimaryQuantity. Add Resources to an Item The next step is to add these resources to the Item. On the Item Catalog tab, select the wall, and go to Use Resource > Use Existing Master Resource.

Here you can expand open the folders and holding the Ctrl key down, select the relevant resources that make up the item, then click Use in Item, these will now appear with spanners underneath the item.

Note. If you select a resource you can modify these for that particular Item, any overrides will appear in bold to show they aren't using the standard formulas, this may be used where an item is using a resource in a non standard way. Now each time you take off a wall, it will also work out how many bricks, blocks, wall ties, insulation and wall ties you will use. Modifying the catalog You can easily move Items to different parts of the Item Catalog (the same applies to Resources), in the Item Catalog simply right click the item or folder you want to move and Cut and Paste it into the new place, if anything has already been taken off to that item it will also bring any take-offs to the new location. You can also Copy and Paste to create new Items which use similar formulas and/or descriptions, you will however need to modify the WBS in the item. Create your own catalog One alternative way to build catalogs is to use the Navisworks Quantification Catalog Creation template to allow you to easily convert your existing spreadsheets into a Navisworks Catalog with colors, descriptions, appearance overrides and WBS. There are instructions in the spreadsheet, just Enable the content to allow you to use the Export Catalog button under Add-Ins in Excel, I will post more about this in a future post. Once you have your catalog you can export this out and use it over multiple projects, and as you build out your items and resources project by project, you will build out a more intelligent way of quantifying your model. More information on Items and Resources can be found in the following video: - Quantification: Using Items and Resources help video Next time I'll talk about how to take off the model.How to take off items in Navisworks QuantificationSo far we have talked about the rough workflow in Navisworks Quantification and building Catalogs in Navisworks Quantification, now we get to the fun part (at least for me), taking off objects. There are three types of takeoff, Automated takeoff where properties are brought across from the model Manual takeoff, where you will need add the properties yourself Virtual takeoff where you takeoff an item that hasn't been modelled Automated Takeoff Let's start with how to take off an object that is in the model, you'll be able to add objects at Composite Object level (in the selection tree this has a box with a cross on), that has a GUID (a unique ID to identify it). So taking a sample Revit model, either exported NWC or imported RVT file, you will be able to change the Selection Resolution to First Object (under Select and Search in the Home tab), then follow one of these methods to take off the object to an item in your previously created catalog. In the Quantification Workbook find the relevant Item or group to add this selected item to, you can create a new item as part of this group if the item doesn't yet exist. 1) Model Takeoff > Take off to Selected Item or New Item 2) Drag and Drop to Quantification panel with an item selected, this won't work if you have a group selected.

3) Right click > Quantification > Take off to selected item or new item

As with most of the major features in Navisworks, the most effective way to run the process it to build up relevant Search Sets based on properties in the model, in this case this is important for the first run, these can then be reused between projects and keep up to date with changes in the model. Create the search sets for the level of granularity you want the takeoff to be run in, for example all steel beams, or all steel beams using a particular grade, or all steel beams using a particular grade on Level 2, or all steel beams of a certain thickness on Level 2. Then takeoff the objects using one the methods above. If you try to take off a model object that is an instance, or if the object does not contain a GUID or properties, an error message is displayed. Note. If you are using Searches, we recommend you take off objects initially using the Search set, this will take off all the objects in the search at that time, on subsequent passes this will take off objects multiple times if you blindly accept the warning. Use the hide takeoff feature to see what new items need taking off in subsequent passes. Manual Takeoff Sometimes you won't get the necessary property in the model for example you want a property 'Beam Height' rather than just 'Height' or this is a file we have not yet created mappings to yet. Where a property is not immediately picked up, it is possible to add a new mapping to it, we have a guide to mapping properties if you want to have a go yourselves, otherwise Autodesk Consulting or your partner can provide services to build out a mapping to the products you use. Otherwise you can still add the properties manually. If the property you need is in the Properties Panel (normally under the Element tab for Revit, or Civil 3D tab for Civil 3D, etc), then you can right click, and copy the value, then paste it into the relevant cell, this will take in any formulas you have set up. For example you may want to manually add a ModelHeight as the ModelWidth and ModelLength are available but Height is listed as Unconnected Height, you then have a Volume formula of =ModelWidth*ModelLength*ModelHeight which takes the Width and Length you have automatically mapped, and the Height you have manually added to create a volume value. If the property is not available at all you may want to use the measure tools which have been revamped in Navisworks 2014 to get the value from the geometry. By taking a measurement (the cross indicates a corner, and you can zoom in by holding Enter and using the + and to change your zoomed view), you can check the point to point values, an area, a perimeter, or a diameter to calculate a round area from, these can then be added to the relevant part of the takeoff. By using the Convert to Redline tool, then using the small camera button to the right of Virtual Takeoff, this will save a Viewpoint with that measurement for reference that will be attached to that taken off item. Virtual Takeoff Virtual takeoffs can also be created to represent items that have not yet been modelled but will need to be accounted for in the final takeoff,This may represent an annexed building, a missing beam or a surface that may need additional treatments or finishes. These un-modeled items can be key components of a project and need to be quantified along with the modelled object to get a "complete picture" of the items you will be including in your project. In addition to acting as a holding place you can attach views, markups, measurements, and comments, helping to communicate the virtual item in context with the rest of the model. To create a Virtual Takeoff, simply select the relevant catalogue item you want to create a virtual takeoff for, then select the Virtual Takeoff option, you can then manually add the dimensions you'll need and create mark up and measurements using the review tools as we did earlier and save the viewpoint using the camera button. In our next post I'll go through a verification and validation workflow that estimators will want to use when transitioning away from traditional takeoff methods. This should gain trust in the measurements from the model and help address issues immediately for incorrect figures.