How We Came to Draw AV in 3D and the Pitfalls of Revit

  • It was back in the late '80s when the AV industry started putting down the pencils and stencils and began moving toward computer aided design (CAD). The wonderful folks at Autodesk brought us AutoCad, and the face of creating AV drawings was radically changed forever.
  • CAD provided us a means to quickly and easily reproduce drawings with amazing detail, clarity, and accuracy. Bond paper and sepia reproductions were replaced with in-house high-speed plotters and outsourced blue printing services. CAD was a great tool — our drawings looked great, and we could reproduce drawings with incredible speed. We began “cutting and pasting” elements from one drawing to another in efforts to save time and utilize previously created work.

CAD leaders then started the concept of the “CAD library,” which was to be a collection of drawings, details and “blocks,” which could be called upon as building blocks for future drawings. We started standardizing on symbols, notes, legends, callouts, line thicknesses, fonts, and wall types. “Standards” for just about everything we were drawing began to appear.

We could now make drawings faster. And we certainly were making mistakes faster.

Layers appeared, and the 2D world of drawing gained depth. We could now assign drawing “layers” for just about any element of a drawing. We could overlay floor plans, electrical plans, reflected ceiling plans, and so on. And we did. “Layer management” became a daunting task and keeping track of what was on each layer — and carrying some resemblance of uniformity amongst multiple CAD persons within a firm — became a task. Hence, the CAD Manager was born.

The next challenge came when the great minds at Autodesk convinced the architectural world that they could now begin to collaborate their drawing sets so that engineers and consultants could all work together on the same “backgrounds” to produce a fully coordinated set of project drawings. The Autodesk pitch talked about using “standardized symbols” and a “defined layer schedule,” which would ensure all consulting disciplines would be coordinated. The intent was to assign specific CAD layers for all to create their drawings, including the architect, HVAC, electrical, plumbing, lighting, telecommunications, and AV. Color became a part of the mix, and now our 2D drawings not only had depth, but they were brought to us with 256 colors available per layer.

It’s unfortunate, but even after three decades of drawing in 2D, I can say that real standards for how CAD files should be formatted for unified collaboration across multiple disciplines (architectural, engineering, consulting) never came to fruition. Sure, we have been able to share drawings across disciplines, but formal, workable standards have never really been universally adopted. Each project drawing set has its own set of rules, layers, and formats, usually dictated by the project architect.

Now here comes Revit. Let’s take all the craziness and capabilities we have in 2D and give it a try in 3D. We must be gluttons for punishment. Once again the marketing folks at Autodesk have convinced the architect that Building Information Modeling (BIM) is the future of drawings.

Most of us do not realize how complex drawings now become when moving from a 2D to a full 3D model. The answer is: VERY COMPLEX. Engineers and consultants are kicking and screaming as we follow the direction of 20-plus different architects, each providing varying direction on how their project models will be created. As silly as it may sound, there are even different project suites within the same architectural firms developing different format project models. Insanity is spreading. Project kickoffs now include “BIM Coordination Meetings” where the rules, formats, and methodology of how the BIM model will be developed across the multiple disciplines working on the project are discussed. It’s the Wild West all over again. The rules of engagement are still vague. A new concept has evolved, Clash Detection, where CAD folks spend hours together trying to resolve conflicts in the BIM model.

Each project model is different, and the amount of time we are spending on drawing in Revit has tripled our workload.

For us in AV, it makes sense to include any equipment that touches walls, floors, or ceilings in the BIM model — items like projection screens, video projectors, ceiling speakers, wall/ceiling cameras, flat-panel mounts, wall boxes, and floor boxes. For these items, most manufacturers provide Revit models of their equipment, and frankly, I would rather just hand these over to the architect and ask them to include these in their drawing model. Most BIM models do not yet accommodate all the nuances of a complete AV drawing package. AV conduit (typically under 3 inches) is not included in most project BIM models. AV conduit riser drawings are still 2D, as well as AV system flow drawings, and AV cabinet/rack elevations. Most project drawing packages include a mix of 3D and conventional 2D drawings, which are now referenced in the BIM model.

I will say that as an architectural tool, Revit is very impressive. If you take the time apply all the finishes and develop all the views, the 3D rendering and walk-through capabilities yield some very impressive imagery. Autodesk has provided us with another wonderful tool, but for AV, it lacks the proper direction or published standards on how it should be implemented. I find Revit to be another dangerous tool that will no doubt hurt us long before it helps us.