Bridging the gap between schematics and reality

Over the last year I’ve been working to devise a convenient way to design cable paths. What I mean is to be able to show locations of equipment on architectural plans, and the paths of conduits, trunking or cable tray that will carry the cables that inter-connect the equipment.

It’s a problem that’s nagged me for many years. At one point in my life I was involved in designing broadcast TV signal distribution for a large international sporting event. As a design experience it was like wrestling jelly.

Real world cable path design is not a stately progression from schematic to details of trays and conduits . There are big rocks in the road. When you get to the site you’ll find problems like the aircon people have filled your hole in the concrete with their duct. And that’s not all – you get caned for over-capacity and vilified if the pipes are too narrow. It’s a no-win situation.

As a broadcast or audio-visual designer, the detail of cable-carriers are not your job- electricians do that. BUT they need a specification to work from. They need to know where the ends of the cables have to be, how many cables of what type go from where to where, and maximum lengths and bends radius limitations. So they need a plan like this.

Cable Path Specification
Cable path specification

Your boss will also be nagging you for an estimate of how much cable long before the electrical contractor can give you actual path lengths. So… in fact you do have make your own design of cable paths. Only by modelling in 3D can you really get a proper estimate of the lengths.

3D Cable Path Model
3D Cable Path Model

But, you definitely don’t want to show that to an electrician. In the construction industry people are trained to seek any opportunity to avoid responsibility and throw blame on others. So if you hand your electrical guy a plan like the one above, regardless of practicality he’ll go put the conduits exactly where you drew them and produce your drawing if anyone complains.

So our problem becomes one of making fast convenient tools to do a fairly detailed design for estimation purposes but be able to present it as a specification drawing with paths shown as  arcs, plus a “riser diagram” which just shows connectivity.

Riser diagram
Riser diagram

We also have the problem of finding the cable tray fills. If we have a schematic of our system or a cable list then we know the theoretical inter-connections. So it then becomes a case of assigning physical paths to these. In many cases (but not all) there will be only one path. Analysing cable tray networks into discrete A->B paths is not altogether simple since there may be loops in the topology.

As you can see from the drawings above, we’ve been making progress. However…

In to all this soup came Revit. The reality is that more and more projects are beginning life as a Revit model. That raises many questions.

We wanted to bring cable path planning into connectCAD 2016 but our feeling is that we need a closer look at where our data is coming from. The days of 2D plans and elevations are numbered. Perhaps the question is a different one? How can we depict cable paths in Revit and extract their topology, connectivity and lengths?

Has you’re life as a designer brought you in contact with this? Comment below. It’s good to talk 🙂