Like any CAD or BIM software, Revit is only as good as the information you put in, and the last thing we want is to walk down the road and spot a Revit Building, recognisable by the styles of windows, doors and features it is constructed from. It is therefore essential to establish good libraries and we cannot rely on the default supplied components but rather than a painful hindrance, a well thought-out and constructed library can turn groups of Architects, Engineers and technicians into near mythical superheroes in terms of the production output.
When using Autodesk Revit software, we cannot save system families such as walls, floors, roofs, ceilings, stairs and railings into a library in the same way that we do with standard families such as windows, doors, light fixtures, etc. Inspection of the default Autodesk-supplied libraries will reveal a folder of system family example projects where a number of sample styles have been established and demonstrated. If you wanted to use one of these samples in a project then you can open one of these project files and copy and paste the required element style across or use Transfer Project Standards in order to get them all.
Another solution however, is to use the group functionality, and this is what has recently been made available in an exemplar Knauf catalogue of internal wall styles. The intention in releasing the library is to provide advice and guidance on how to establish system family libraries. The manufacturer supplied the information contained within but has not endorsed the library in its current form in any way, but that is not the point of the exercise – it is a learning aid which can be modified easily to suit specific working requirements.
This is a pretty picture of a wall and not indicative of the
best-practice advice on how detailed to make your models!
The process of creating the library is briefly described here, and the workflow would be as applicable to libraries of staircases, ceilings, floor slabs and roof construction as they are to the definition of a wall library in this case.
I started with a blank project and first defined all the materials that I wanted to include in my catalogue. These materials do not simply have the correct hatch patterns applied and render texture associated, but they include lots of manufacturer meta-data – the product name and code for instance, the performance properties for such criteria as impact, sound and fire resistance – remembering that we are still talking about a theoretical material at this stage, and not a specific thickness of that material. By this I mean that the properties that we apply at this stage should be carefully considered if varying thicknesses will be used to build wall or ceiling compositions. So if a gypsum board is available in 9.5mm, 12mm and 15mm then we cannot state the fire rating as a fixed number but could perhaps give a fire rating per millimetre of thickness if that was relevant to do so. That said if the board only comes from the supplier in a single thickness, then we can obviously be more specific. In the case of the sample Knauf library, I have kept things fairly safe.
The next, and fairly laborious task, was the definition of all the different wall compositions that used these materials in different configurations. These walls then had another layer of meta-data applied to them, this time referring to specific properties of the correct thicknesses of materials in the given combination, so maximum unsupported height, acoustic and fire rating, etc.
Having created, named and propertied all the wall styles, I turned my attention to the fabrication details. I had a relatively small number of standard details that I wanted to include, such as corners, tee-junctions and cross-junctions, all of which assume 90deg angles – I did not want load the components with the logic and parameters to allow variable angles as this would place heavy constraints on the hardware in anything but a small project (and it would be difficult!). I analysed the standard details and broke them down into composite parts, such as a standard C-profile section, a silicon expansion joint, a board extension piece, etc. These were then created as 2D detail families, and whilst they are fully parametric to maximise the usage and minimise the need for variants, it is important not to try and make one component the answer to all scenarios, so if a component has various optional additions, I would tend to opt to create several different families.
Having established my mini library of detail components, I then compiled those into a series of more advanced detail families which are intended to convert the default wall joins into the approved standard details. This involves masking out incorrect parts of the underlying 3D model and then adding new filled regions and 2D components. The parameters of the constituent parts are nested across into the new detail families which, in simple terms, mean that when I change the properties of a corner junction to adjust the thickness of the structural core of the wall, then the C-section detail component expands to fill the gap accordingly.
There were four variants of each detail to create – namely single board and double board each side of a single metal frame, and then the same for a double frame. The parametrics meant that these four could then be adjusted to suit the different thicknesses of board and different sizes of C-section frame.
The next creation stage was to define some tags which extracted certain bits of the information contained within the walls and deeper within the materials as well. Finally in the project I used the repeating detail tool to define the C-section frame at correct spacing.
All the detail families were all loaded into the project, and then a seemingly bizarre little shape was drawn using the first wall style which allowed me to test the corner, the tee, the cross and the stop-end. I also draw some lines which represented a floor and a ceiling so that I could check the deflection head and base junction, even though this was all worked up in plan. I also added the various tags to the scene.
Once done, this little group was arrayed and then I commenced the seemingly endless task of changing the wall style and associated details to the correct types and checked everything over. Each one was grouped and named appropriately before been saved externally as an RVT project file of around 1Mb.
To use the library, you do not use the Load Family button but the Load As Group button which will bring in the collections of walls, arranged in a strange pattern, but this will never be seen and can be removed again from the project. What is important is that by bringing the group in, it brings in all the various materials, textures, tags, detail components and repeating details as well as the wall type ready to swap out your conceptual walls in the project with a fully defined and information-rich alternative.
It would be a lie if I told you that the whole process went as smoothly as described above. I did build the specification as I worked and suffered more than one last-minute change which then had to be re-applied through the whole library, but it would be naive to suggest that you can completely stop that from happening. The power and efficiency of applying these techniques across the board is worth the effort however, and as I am sure you can appreciate if you try this sample out, it will make a huge difference to the way in which designs are progressed through to construction detailing.
Following this concept further on, think about creating Style-Packs which include all the required components and information to progress a project for a particular client or type of building. A scheme could be developed from a single default corporate template of concept elements and then a Hospital Pack or School Pack for instance could deliver much of the required kit to take the design forward.
The complete sample pack with all the components and sub-elements mentioned above is available to download from www.andekan.com.
