Thursday, 9 April 2015

Vertical Cable Tray Orientation

A Revit Electrical discipline wish that has been on the list for quite a few years, is to draw vertically oriented cable trays. Natively, this is not possible in Revit. Even though this is unfortunate, there are solutions to the challenge.

This entry will show the pro’s and con’s on the workarounds currently used for vertical (face-based, if you will) cable trays.

As can be seen from the image below, the thick red line will indicate my cable tray route. In this particular instance, I would like my cable tray to be vertically orientated against my wall.

I have drawn a cable tray using the “normal” method of starting the cable tray command, specifying the height and width and drawing the cable tray route.

Trying to rotate the cable tray in section is not allowed and will give an error. This is due to the fact that a cable tray is a Revit system family. In other words, it is created in the project environment (Part of the coding) and is a linear-based object (You draw a route, and Revit creates the 3D cable tray geometry).

The workaround to the problem above, is to first place a cable tray fitting at the correct elevation, even before drawing the cable tray route. Rotating the cable tray elbow will allow you to then specify the orientation. Using the cable tray connectors at both the starting and ending points of the elbow, you will be able to draw a cable tray run on both sides. The drawback to the method above, is that the cable tray run (being a system family) will not be oriented correctly.

One can create a Generic Model Line Based family using a cable tray profile, to orientate the cable tray correctly. One will however have to choose the family category carefully, to ensure that the cable tray schedule will populate correctly, filters will be used correctly, etc. (Remember, a cable tray is a system family. Thus one cannot create a system family category in the component family environment)

The image below shows the graphical difference between the Method 1 explained at the start of the entry, as well as using the custom cable tray run family (Method 2) shown above. 

I firmly believe that for the MEP discipline, we do not over-model in our project, nor in our families. Is it really necessary to see your cable trays correctly orientated in 3D? Or will your plan views convey the correct information? Pretty versus functional? I will leave the decision up to you.

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