Frequently Asked Questions

• What is a COBie "Name"?
• What is the difference between COBie Spaces and Revit Spaces?
• What is a COBie Zone?
• Is there a limit to how large my COBie export can be?
• Why are my COBie parameters grayed out in my nested families?

What is a COBie "Name"?

COBie requires that the value in the first column of every worksheet is unique. This is the Name field in COBie and is commonly referred to as the row name. Some worksheets in COBie will contain data exported from multiple family categories in Revit. For example, Revit Rooms and Spaces will export data to the Space worksheet in COBie; Revit Doors and Windows export to the Component and Type worksheets in COBie; etc. Revit also requires unique values for some categories (for example, all Rooms must have a unique Number value). But, Revit does not require unique parameter values across different family categories. For example, a mechanical equipment family (such as a VAV box) can have the same Mark value as an electrical equipment family (such as a motor control center). If both of these elements were exported to Revit, and if only their Mark parameter was used for their row name, your COBie worksheet would not be compliant, as you’d have two rows with the same value.

What is the difference between COBie Spaces and Revit Spaces?

Autodesk Revit has two different elements to track area and volumetric spatial data in buildings – Rooms and Spaces. Rooms are typically used by architects, while Spaces are typically used by mechanical/electrical/plumbing engineers. Both Rooms and Spaces contain parameters for identity data (like name, number, and associated level) and spatial data (like perimeter, area, and volume). Rooms also contain parameters for architectural data (like finishes for floor, baseboard, walls, and ceiling), whereas Spaces contain parameters for engineering data (like airflows, power and lighting loads, and energy analysis assumptions). Families placed in a Revit model – which are used to represent furniture, fixtures, and equipment – understand that they are contained within Rooms or Spaces and can report the data from them (for example, the name and number of the room they are in).

COBie only utilizes one element for spatial data, Spaces. Because of this, it is important that you define which Revit element – either a Room or a Space – a particular piece of equipment uses to report its location (since it could be located in both). The COBie extension handles this by providing an option in the Settings to choose, based on Revit category, whether spatial data is exported from the Room or Space. For example, you may choose that Door elements (Door being a Revit category) take their spatial data from Rooms, but VAV boxes (part of the Mechanical Equipment category in Revit) take their spatial data from Spaces.

Another consideration for Rooms and Spaces is around the fact that Revit will allow a Room to have the exact same name and number as a Space, since it considers them two different categories of elements. This means that you could have a Room named “Office 101” and a Space named “Office 101” in the same model. Of course, if you exported this data to COBie, you would now have two rows on the Space worksheet with the same row name, which is not COBie compliant.

What is a COBie Zone?

In COBie, Zones are the grouping of Spaces. A COBie Space can belong to more than one Zone. In Revit, the only zone tool is called HVAC Zones and it only applies to Revit Spaces, not Rooms. It is designed to assist with heating and cooling load calculations and is not setup to be used as a general grouping tool for Rooms and Spaces. It is possible to “assign” Revit Rooms and Spaces to a Zone by using a custom parameter (even one that is part of a key schedule in Revit), but this will only allow you to assign one zone per Room or Space.

Is there a limit to how large my COBie export can be?

Microsoft Excel has a limitation with regards to the amount of data it can hold. It is approximately one million rows of data and can be reached very easily if you export every element in your model along with their custom attributes. As an example, if you have just 100 additional parameters that you have selected (on the “Attributes” tab of the COBie Extension setup) and you try to export 10,000 elements (which is not difficult with a large model), then you’ve already reached the 1 million row limit (multiplying 100 x 10,000).

Why are my COBie parameters grayed out in my nested families?

Autodesk Revit has a limitation where instance parameters on shared and nested family created directly in the FRA file are non-editable at the project level. The solution is to remove the COBie parameters from the family in the Family Editor if the family is going to be shared and nested. This will then allow the COBie parameters that are added at the project level to be set, edited, and updated.