by Dennis Collin
When working in an MEP environment or with site models there is a need to be able to communicate the locations of openings in various elements such as walls , slabs but also beams and other elements where a ‘door’ or ‘window’ element is not appropriate. These openings are used to route such services such as pipe, ductwork or electrical containment containing wires and cables. By including such features element clashes with overlapping components can be avoided!
Fig 1. The ‘edit sketch’ approach is time consuming and cumbersome.
Whilst some cumbersome in-place modelling or edit sketch methods can be used to provide openings, it is a somewhat slow and tedious process and in the event of any model changes, takes time to update the changes. Linework if required, is an additional drawing process and will not necessarily update with changes!
Fig 2. For this scenario, using a face-based component is recommended.
For the best outcome in this situation, I would recommend a custom component family should be used and by using a Face-based component family template a generic void element can be created which can be set to cut through any hosted element that it is placed upon.
Fig 3. Ensure the family is set to a ‘sensible’ category!
As per family creation best practice, set the category of the component as site or similar, with a subcategory setting of openings. This will provide flexibility for visibility controls withing the Revit model.
In the family plan view created a constrained framework of reference planes driven by an equalised Width and Height parameters. For maximum benefit (schedules and tags) use shared parameters because family parameters cannot be scheduled or tagged.
Fig 4. Once properly setup Shared parameters are so easy to implement and use!
In the front or side elevation view place another reference plane and constrain it with a suitable ‘Depth’ parameter.
Assuming the framework flexes as desired, a void element can be created (usually use an Extrusion) snapped to the reference planes and locked to the length, width and depth parameters. The void geometry can then be cut onto the reference host to provide an opening.
Fig 5. Family’s Section view showing depth and cutting elements.
When showing openings in drawings, a typical convention is to show a hole with some dashed linework. This can be achieved by drawing some Symbolic lines which are snapped to the reference planes of the family (typically, dashed line style).
Fig 6. Use symbolic lines to show clearance and opening extents.
Symbolic lines will only show in appropriate views, but if the linework needs to be shown in 3D views as well, use Model Lines to complete the opening component.
Fig 7. Shared Parameters can be tagged and scheduled along with Revit’s In-built parameters.
Once saved the element can be loaded into a project or stored in a project template and used as required. Being a component it can have its location identified, its size scheduled (if using shared parameters) tagged and can be edited to suit the progress of the design.
Fig 8. Bespoke Opening families labelled in a project.
A similar approach can be taken to model below ground services, draw pits and inspection chambers, along with rotatable electrical containment and cabling. These examples I will discuss in a future post.
Creating families and parameters are some of the topics covered on our Revit content training courses. Visit the Arkance UK site to get an overview of the courses on offer and talk to one of the team for dates and availability or if you have more bespoke requirements, just ask, we are here to help!
Fig 9. Some custom family examples in an infrastructure type model
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