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    By Dennis Collin

    Revit MEP has been available for a number of years now, the 'E' part, Electrics is definitely the least developed of all the 3 services that MEP caters for. In the early days I always joked in training that it was Revit MeP. (Little 'e')

    However, cable trays was released in the 2011 version along with conduit containment which was a step forward. But strangely nothing was provided for trunking elements.

    Now of course there are a number of 'workarounds' to cater for this missing object type. One tool for example is the Architectural Wall Sweep Tool, which allows the creation of a swept profile that will become of sub-catagory of walls (wall sweep). This is normally used for things like cornices, dado rails and soldier banding details in walls.

    The tool is also helpful as it lets you define horizontal and vertical elements and stretch the end points as desired. It is also wall hosted so the element will automatically move with any wall changes.

    Different Options being used as 'Trunking'

    Disadvantages include, the catagory the element falls in, and corner clean-ups, they look clean but they do not have the elbow fitting that is often present. For T junctions the Join command will need to be used. A major disadvantage to the MEP Engineer is the Sweep tool will not work on Linked Model Walls! The last thing you want to do is remodel the building!

    Another option perhaps, is to use a face based component family using a catagory like speciality equipment, rather than the rather bland descriptive 'Generic Models'. Using the Sweep tool one could use a Profile element like the Wall Sweep command as above. Although you may need to create two families; one for vertical and one for horizontal elements. However as above, similar compromises apply namely the corner clean ups, joining geometry and the catagorisation issue. But at least it will work with Linked Files!

    Another alternative that I have suggested to some of my training delegates is actually use a Duct element instead!

    The catagory will still be incorrect and you may not have a chamfered shape option, but normally, in most instances the precise look of the trunking doesn't matter, or the trunking profile is almost rectangular anyway! In my mind this is the closest thing to what we actually need. Also because we are using a fittings family, the schedule will more closely reflect what would be need and is installed on site! When you turn corners fittings will be applied like Duct and you will be able to place face based sockets and ports.

    The bottom line is any of these options mentioned is a compromise, you simply need to look at what does the project require, and apply a best fit solution. In my view a Duct in Trunking clothing is a good potential option.

    All you need to do therefore; is  to duplicate a Duct family and rename it as Trunking. You further might want to distinguish this element by creating a Trunking Duct System and add a type comment as 'Trunking' to aid in view and scheduling filters. It is also advisable to do the same for all the elbows and fittings with regards renaming , and applying type comments. because these will be need to be filtered to ensure that Ducts and 'Trunking' won't appear on specific service views. You will also need to use the Align lock function to ensure the trunking follows any building shell changes.

    Access View Filters via Visibility Graphics Overrides

    or for Schedules below..

    To distinguish elements for Filters I would suggest Type Comments is probably the best field to use for this. For Visibility Graphics the Filters option can be used and then applied to a View Template which is an invaluable method of ensuring views look and stay consistent. Schedules can be filtered in a similar way and ideally should be setup previously in a Project Template.

    The Visibility Graphics Filter below is an example of how users can separate their regular Ducts and fittings from the Trunking 'Duct' System. 

    Basically if a Duct object doesn't have Trunking in the Type Comments, it will not appear in that view. A schedule could be filtered in a similar way.

    For drawing views these Filter Overrides can be saved in a View Template which I will discuss and explain in another blog.

    We are now approaching the time of year where we will soon be installing new versions of various Autodesk applications. I for one am hoping for some big improvements in Revit MEP. there are so many areas to be improved; namely the inclusion of trunking, revision control and management, schematic views, content and wires to name but a few!

    Until that time comes however, I will continue to blog and try and offer suggestions and workarounds to these tools and hopefully it will make your day easier whilst trying to get to grips with BIM and that single model environment.




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