How To Use Bomtable For Counting Hangers In Autocad Mep: Unlock AutoCAD MEPs Secret Weapon: Automate Hanger Counts with BOM Tables
A BOM table in AutoCAD MEP is not just a static list; it is a dynamic, database-driven report that extracts real-time data from your model’s underlying information. For counting specific objects like hangers, this dynamic link is what makes the tool so powerful, as the table updates automatically whenever you add, delete, or modify hangers in your drawing. The process begins with a clear selection, as the BOM is generated from a specific set of objects you define, making your initial selection strategy crucial for an accurate count.
To start, you must first select all the hanger components you wish to count. Use the appropriate selection tools, such as a window or crossing selection, to grab every hanger in your system. You can also use the Quick Select feature to filter by object type, targeting objects with a service type of “Hanger” or a specific part family name. Once your selection set is ready, initiate the BOM command by typing `BOM` in the command line or navigating to the Output tab and clicking the Bill of Materials panel. This action opens the BOM palette, where you will build your report.
The core of the process lies in configuring the BOM filters to isolate only the hanger data. In the BOM palette, you will see a default table structure. Click the “Select Objects” button if you haven’t already, then use the “Filter” button to open the BOM Filter dialog. Here, you apply rules to exclude everything but your hangers. The most effective filter is typically based on the “Object Type” or “Part Family” column. You would set a condition like “Part Family” “Contains” “HANGER” or “Is” “Hanger – [Specific Type]”. This step removes pipes, fittings, and other equipment from the count, leaving only the support elements.
After applying the filter, the table preview will populate with rows corresponding to your selected hangers. The default columns might show generic information. To make the count meaningful, you need to customize the columns. Click the “Modify Columns” button in the BOM palette. Add columns that provide the data you need for counting and identifying, such as “Part Number,” “Size,” “Hanger Type,” or “Service.” You can also add a calculated column for a simple quantity, but the primary count comes from the number of rows for each unique combination of your chosen columns. For instance, if you group by “Hanger Type” and “Size,” each row represents a unique type, and the quantity column tells you how many of that specific type exist.
The resulting table gives you a categorized count. A row might read: Hanger Type: Trapeze, Size: 4″, Quantity: 12. This means there are twelve identical 4-inch trapeze hangers. To get a grand total of all hangers, you would sum the quantities in the final column. You can do this easily by exporting the BOM to a spreadsheet. Use the “Export” button in the BOM palette and choose a format like XLS or CSV. Once in Excel, you can use a simple SUM formula on the quantity column to get your total hanger count, and use PivotTables for more advanced analysis of types and sizes.
It is important to remember that a single hanger assembly in AutoCAD MEP might be composed of multiple parts—a clamp, a rod, a beam clamp, etc. The BOM, by default, will list each individual part as a separate row if they are separate MEP objects. To count complete hanger assemblies instead of individual components, your filtering must target the top-level hanger assembly object, often named something like “Hanger Assembly” or a specific part family that represents the whole unit. You must ensure your selection and filter are capturing the assembly part, not its nested components. This requires understanding how your specific MEP content library structures hanger parts.
For the most efficient workflow, save your BOM configuration as a template. After setting up the perfect filter and column layout for counting hangers, click “Save As Template” in the BOM palette. Give it a descriptive name like “Hanger_Count_Template.” Next time you need a hanger count, load this template, click “Select Objects” to grab your new hanger set, and the table will instantly reconfigure with your saved settings. This eliminates repetitive setup and ensures consistency across different drawings or projects.
Finally, always verify your results by cross-referencing with the model visually. Use the “Highlight” function in the BOM palette to select a row and see the corresponding hangers flash in the drawing. This confirms your filter is capturing the correct objects. Also, be aware that changes to the model after generating the BOM will not automatically refresh the open table; you must manually click the “Refresh” button in the palette to update the counts. By mastering this dynamic link between your model geometry and the BOM table, you move from manual, error-prone counting to an automated, reliable system for quantifying hangers and any other MEP components, ensuring your material takeoffs and project documentation are always accurate and current. The key takeaway is that the BOM table is a live window into your model’s data, and precise filtering is the control that determines exactly what that window shows.
