Seeing the Wood & the Trees - Landscape with Revit (By Ed Harrison, BIM Manager, Austin-Smith:Lord)
As a multi-disciplinary practice, part of our move to using BIM capable software meant that we had to be able to model anything within the software of choice. We use Autodesk Revit and as most people familiar with the software will know, the landscape side of Revit was never its strong point. The Landscape Institute have been continually working to establish some common methodologies and here at Austin-Smith:Lord we have been developing our own using the LI information as a starting point.
It’s great to be able to model your landscape scheme in a 3D environment and be able to watch it develop through the design process but unless that scheme has the same level of intelligence behind it that your building model has then it can be pretty pointless from a BIM point of view. During the implementation of BIM within the practice the decision was taken to establish our standard method of working as compatible with Level 2 maturity as far as possible. All our in-house Revit content is created using edited versions of NBS family templates. Now, there has been some criticism of NBS with the release of their family templates, but as a starting point for your own content they are very useful and provide a reliable basis. We also edit any externally sourced content including manufacturers libraries with some of our standard parameters to enable some Level 2 compatibility. We have worked on projects, begun using Revit where there is no BIM requirement from the Client who saw the various benefits and then decided to commission the team to move forward at Level 2. Because of the way we work every day, if the trigger is pulled for Level 2 we’re there and ready to go.
Applying this process to projects including landscape and external works and we are able to create tagged and intelligent components that can be scheduled and categorised to suit any Client requirements. We have planting schedules created automatically as soon as the first instance is placed in the model. Each planting type has species specific parameters added within the edited family template. The schedulable fields cover numerous possible requirements and can be as detailed or as brief as the project demands. Street furniture has also been created in the same way, all of which enables accurate counts and costings should a cost consultant need to interrogate the model.
In line with recommendations from the Landscape Institute we model all hard landscape surfaces as floors. While to some this may seem a crazy way of creating areas of paving or gravel it is the best method we have used that works with the level of intelligence that is required. A quick look at the lack of functionality in Revit topography told us that trying to work with those types of surfaces was a non-starter. With no way of adding construction depths or indeed, patterns to a topographic surface, let alone asset tags and COBie data the only sure fire method of adding this information was to use floor types. Again, using NBS content from the NBS BIM Library, we adapted various hard landscape surfaces to suit our requirements. Falls and slopes to the surfaces are created using various methods and are accurate to correct levels related to the correct project datum.
Kerbs, edgings and profiles are added using slab edges and the dreaded ‘in place family’. I use that term deliberately as in place families in Revit do come in for some criticism but as long as they are used sparingly and efficiently they can be the only method of adding the correct profile to complicated geometry and allowing the previously mentioned intelligence to be added. Without that intelligence something like a kerb line of 200m length is pointless so it must be done in Revit.
But why Revit, why not use Civils 3D or some other design authoring software much better suited to landscape projects? There is a simple answer to that, Revit is our software of choice for all our architectural projects so to add another package into the mix means time and cost for staff to become proficient and competent. Revit allows us to work across the ASL team with full confidence in compatibility and knowing that the same standards and levels of data are included in all our project types. Yes, there are limitations with the landscape modelling but we have worked through them and continue to do so. We have developed methodologies for overcoming issues that are contained in a guidance document that all the teams use & follow.
Project example used: Wigan Transport Hub