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.