Creating a quantity takeoff breakdown structure Estimated reading: 5 minutes 955 views Creating a new quantity takeoff Click on the arrow next to the New button → Select the Blank Quantity Takeoff… → Set the name of the quantity takeoff in the Name field → In the Type field, choose elements for desired quantity calculation, distributed by certain rules → Click Use Selection → Define the rules for quantity breakdown structure by clicking Add Breakdown Rule → Add quantities by clicking Add Breakdown Quantities → Click Generate → Finish the process by clicking OK. The Type field is positioned on the left part of the window and is used to choose elements for desired quantity calculation. There are several options for selection: by Buildings, Building Storeys, Categories, Families, Selection Sets, and Elements. The Elements option is active when quantity takeoff is created from a selection of elements before the start of the quantity takeoff actions.On the right side of the screen, define the rules for quantity breakdown structure depending on planned results, and add the quantities and unit type:Click Add Breakdown rule → Define the first criteria for the quantity takeoff, for example, Group by Category → For adding a new grouping rule, click again Add Breakdown Rule, Group by Family. To add a new rule, click Add Breakdown Rule or find the same commands using right-click on the desired item in the breakdown tree. For adding quantities, select Quantities → From Add Breakdown Quantities drop-down menu, choose Add Quantity… → The Select Quantity window will open → Select a value, for example, Area → Confirm the selection by clicking OK → In the same way, add other parameters to obtain more quantities for selection. To add quantities, use Add Quantity… or right-click on the breakdown tree and choose commands for adding quantities – Add Quantity…, Add Discrete Quantity…, and Add Count. For some parameters, such as Area, you can change the unit of measurement and adjust the quantity formula. In the Select Quantity window, in the Aggregate function field, determine which function will be used: the Sum, the Average, etc. Click Change… in the Unit field to select the desired units. Quantity takeoff commands An Add Breakdown Rule command will group BIM elements by defined rules. In the drop-down list, choose between predefined rules, such as Building, Building Level, Category, Family, Source, System Name, Material or specific rules using group by Selection Sets, Property or Multiple Properties, Property Range, or Containing Material. To eliminate the rule or the quantity previously selected, use Remove.With Move Up or Move Down, organize the hierarchy of rules and quantities.Reset Tree will collapse the tree to the primary position.Discrete Quantity defines the text from the element property as a rule (for example, Workset).Count is a parameter that gives the number of individual elements within the quantity takeoff.Option Display Elements Distributed in Multiple Positions is disabled by default. If this option is enabled, all elements distributed in more than one position in Quantity takeoff will also be organized under group Multiple Selection Sets.Option Enable Elements Multiposition is enabled by default. If this option is enabled, all elements within the breakdown structure, even if they are already counted within another position, will be distributed as was defined by quantity takeoff creation rules. This option is used when one element is used for counting more than one position in the quantity takeoff. If the option Display Elements Distributed in Multiple Positions is disabled and Enable Elements Multiposition is enabled, the software will create a warning if there are multi-positioned elements in created quantity takeoff breakdown structure. Be careful in this situation to avoid double quantities and possible mistakes. Creating quantity takeoff from selected elements To create QTO from selected elements, select proper elements using a family from the appropriate category in the structure or a particular selection set. Then, isolate selected elements in the main Perspective view.The only difference between creating quantity takeoff from blank and selection is that previously selected elements are automatically defined under option Elements in the field type.Set the name of the quantity takeoff in the Name field → Click Use Selection → On the right side of the screen, define the rules for quantity breakdown structure depending on planned results, and add the quantities and unit type (see Creating a new quantity takeoff) → Click Generate → Finish the process by clicking OK. Updating quantity takeoff After updating the project, on the right window of the Quantity Takeoff palette, by clicking the Load button, created quantity takeoff will be automatically refreshed with updated element properties.
