In 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
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.
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
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.