If you are a new Revit user you might be wondering what different kinds of families can be created and how to differentiate them. This post will help demystify and inform you!
2D and 3D Revit families
We introduced Revit families in a previous post. Whether you are new to Revit or an experienced user, families are one of the most important building blocks for use on your projects. Thus, it’s important to properly understand the different types available and how to define them. Firstly, we can define 2D and 3D as a main division (albeit families can combine the two!). 2D families can correspond to symbols and annotations (tags, sections, detail items, etc). On the other hand, 3D families are geometric representations.
Geometric Revit families
Once we get into 3D families, we can further sub-divide them into loadable, system and in-place families:
- Loadable families: these families are created in external (RFA) files and their properties are almost infinite, reflecting the properties of the real product or asset. Loadable families are user-defined families built with the Family Editor in Revit, generally using family templates. Users can define their parametric, graphical and documentation requirements from scratch.
- System families: this kind of Revit family is predetermined within Revit and the assets’ properties are predefined. Walls, ceilings, doors and ducts are examples of system families.
- In-place families: these are executed within the project, being able to take reference of the existing elements. They are generally used to represent elements that are unique to a specific project.
So how can I differentiate them?
The main way to differentiate between Revit family types is knowing that system and in-place families cannot be loaded into or saved out of a project. On the contrary, loadable families can be created and loaded into a project, as well as deleted or saved from a project. In-place families, unlike system families, can also be created within a project using Family Editor tools.
Loadable families are more flexible than system and in-place families. Because it is possible to create them externally and import them into any Revit project, often created by an outsourced BIM specialist. External companies and sub-contractors can prepare loadable families according to the client’s specific needs. But to achieve the required quality, it is important to establish a work standard. There are currently market standards in continuous development and transformation, such as AEC, NBS, BSI, NATSPEC, ANZR, NBIMS-US, to name a few.
Quality and information exchange for Revit families
Additionally, the implementation of not only standards, but also tools for quality control is necessary for a measurable and qualifiable service. Understanding the client’s requirements in terms of information exchange is also critical when developing Revit families. For example, the new BS EN ISO 19650 aims to standardise the information exchanges. This international standard identifies COBie and IFC as the preferred information exchange formats.
Tools for Revit family development
Creating loadable families is generally known in the industry as ‘Revit content development’ or ‘Revit family development.’ We can use different tools in the modelling process to improve and organise information:
- Type catalogs
- Shared and types parameters
- logical and conditional formulas.
- MEP connectors
- Lookup Tables
- Parametric relations
- Photometric files (lighting)
- Identity data and URL links
- Modelling Standards
- Exchange Standards
- Render Material Set-Up
- Schedules and QTO Set-Up
Kinds of loadable families and main services
When it comes to developing loadable families, some of the most common elements in buildings are:
- Architectural families: furniture, doors, windows, etc.
- Structural families: columns, beams, footings, foundations, steel framing, etc.
- MEP families: HVAC, pipe and duct fittings, accessories for plumbing and electricity, etc.
Lastly, the main Revit content development services within the construction & engineering arena are:
- BIM Project-specific content development
- Revit libraries creation (for manufacturers)
- Market products on-demand
- Standards compliant content
At GlobalCAD we are a leading developer of Revit family content. Check out our Revit family service to find out how we can enrich your projects with quality content.