Essays and Blog
Our Revit Experience - Four Years On
In 2007 we decided to move all of our project work over to Revit. Previously we had being using Vectorworks for our drawing work, along with some AutoCad for reinforcement detailing under the guise of CADS-RC. Historically we started the practice using MiniCad, the precursor to Vectorworks. We also spent a couple of passionate but turbulent years in a relationship with Microstation, until they finally dropped the Mac version.
In 2006 we realised that drawing in two and three dimension using Vectorworks was all very well, but surely we were recreating drawing and analysis models in parallel, and so doubling up our workload. We were also conscious of the amount of co-ordination required to ensure that information on plans matched the sections and details, especially as design changes sweep through projects. We were also aware that we were not putting enough effort into standardising the way we were drawing things. We look around the market place and, after a brief and expensive false start with 3D+, we decided to push on with Revit, recently acquired by AutoDesk.
Anyone who has played with Revit for an hour or so will know that there is an initial love affair, followed by a sudden realisation that you are staring into an abyss of complexity. You try to understand Revit by applying tried and trusted concepts gained from using conventional CAD software. You find yourself asking inane questions like “where are the layers?”, or “where are the pen types?”. Only when you give yourself up and accept that the world as you know it will never be the same again, do you finally break through. Concepts like families and parameters start to make sense. We realised very quickly that the only way this was going to work for us was to throw ourselves in totally; if you want to learn French, go to France, speak French, think French, and eat French. So it is with Revit. If you want to learn and use it, throw away conventions and just go with it.
At first it was a struggle, especially as we found that the 2007 version had a number of rough edges that made some things that we wanted to do difficult. However, we persevered and gained some early success. It helped to have a small group, to constantly chat and discuss findings, and to have an evangelical desire to make it work. We quickly established some ground rules;
• All details and connections are to have a 3D view as well as the normal section and plan.
• A standard template was to be used for all projects.
• The creation of parametric elements, known as families in Revit speak, was to be a committee design process, or one that required checking and approval of the element design before it could be incorporated into a model.
The immediate results were stunning. We started to produce some fantastic models, and we saw a 150% increase in measured productivity. The other interesting thing was that the engineers started to think in a different way, using the 3D model before the plan and section, or at least at the same time. All of those mistakes where you get the level of a slab or beam wrong, or have a beam bearing onto a void rather than a wall, just disappeared. We found ourselves listening to our engineers telling their architects about stuff that did not fit.
The other profound, and perhaps most controversial thing that happened was that the engineers were using Revit. Traditionally engineers calculate and technicians draw, which is not ideal, but works fine using Vectorworks and AutoCad, and is the way of the world in structural engineering design offices. Trying to communicate with a technician who is using Revit however, is a whole new ball game. How do you do it? Our engineers were asking us “why do we do it?”. By the end of 2008, all of our technicians had moved on, and all of our work was being done by graduate engineers.
So how do we use Revit now?
• We create site models with ground contours, geological strata, drainage systems, to assess existing levels and establish new levels, using volumes and sectional views.
• We have families for simple components such as bolts, welds, plates, resin anchors, padstones, etc.. These all have parameters that are controlled and prevent misuse, like too close a spacing or too small an edge distance.
• We create composite families for components like column bases with holding down bolts, or glass floors with bearing angles and details.
• We use the scheduling ability to produce quantities and things like column schedules.
• We use ‘phasing’ on retrofit projects, defining the original structure, the demolished elements, and temporary works, and the permanent new works. We also use ‘options’ to show alternative schemes for the same elements in the same model.
• We use ‘work sharing’ to enable more than one person to work on the same building model, and we ‘link’ models where we have larger projects with multiple structures.
• We often start the Revit model almost as soon as the project comes into the office as it is allows scheme concepts to be worked through quickly, providing information on quantities and volumes for comparison.
What has surprised us? Well lots of things, but the most important being that an extreme discipline is required to use Revit properly. Because each project has one model, or a number of linked models, every model must be created properly in a standardised way. The productivity savings can be lost in moment if the wrong families are used, or the way elements are locked to grids is not done properly; there is no roof for mavericks, Revit requires teamwork. Oh, and we do not use Revit models for analysis, not yet anyway; they are too complicated and there is just too much information in them to make the integration worthwhile, especially as analysis software has improved so much since 2007.
In summary, Revit is what everyone thought that CAD was when they were buying it in the 1980’s, only for them to find that they had actually bought Etch-a-Sketch. We love it, and there is no going back.
Finally, we know exactly how much our buildings weigh - Buckminster-Fuller would be pleased !
By the way all of these images are from the same Revit model.
