In the last post we looked at Project Info which briefly mentioned data mapping to IFC fields. In this post we will specifically look at the IFC data mapping in ARCHICAD 18. Whilst there are some great features in the latest version of ARCHICAD, the IFC mapping is definitely my personal favourite new feature. For me, this is real BIM! Rendering is always high on architects wish lists and grabbed a lot of the headlines. However the need to create, manage and check data efficiently is imperative for us as we move towards the UK Government target of achieving “Level 2 BIM’ by 2016.
Before looking at how the mapping works it is important to understand why the mapping is needed in the first place. Over the years experienced ARCHICAD users have developed their own approaches to data. Most architects focus on limited elements such as Doors, Windows and Spaces. Many of these approaches are practice specific. However, for BIM projects there is a need to create data for pretty much all model elements and to create it to standards that allow structured data to be utilised by others. Creating, managing and checking data for the number of Elements/Components and Spaces we are talking about even in modest sized projects means that being able to create this data efficiently and reliably is essential.
In ArchiCAD 17 we moved away from placing data in ARCHICAD’s native parameter fields and began placing data directly into IFC and COBie fields. This meant we aligned our information output with open international standards (including IFC (ISO 16739:2013) and COBie which in the UK is due to become BS 1192-4:2014 very shortly) for others use. This also has the potential to reduce the need for mapping at the receiving application, particularly as more software adopts open principles. This approach also allows this open data to be mapped directly out-of-the-box into native fields into other software such as Autodesk Revit.
We created a workflow whereby we had ‘Favorites’ (see my blog here on that subject) which had placeholders for data. This meant if you selected a Wall from a list that it would have placeholders in the fields we wanted users to complete, aligned with the RIBA Plan of Work 2013. It also showed them when they would need to complete this data. This approach still exists but there were some issues with this approach. The main issues were that in order to create reliable data it relied on users choosing the correct Renovation Status (Existing, Demolished or New), a Favorite (which had the right settings and placeholders) and manually adding a Description to the Component. The last part, the Description in particular was where some of this fell down. Some users would forget to add a Description and the data would quickly become unreliable. The Renovation Status, key Settings (defined in the Favorites) and Description field were, and continue to be, the key items to create reliable information within a model.
So how does the mapping help? Well the mapping adds the ability to take a piece of data that already exists and put into another field. So this means any native piece of data can automatically be placed into a corresponding IFC field. Straight away this means ArchiCAD users with existing processes can simply create a mapping and push out IFC and/or COBie data.
Image: ARCHICAD 18’s IFC mapping is available through IFC Scheme Setup…
So if for example you are putting a Fire Rating into a native ARCHICAD door parameters you can map this to Pset_DoorCommon > FireRating. However the mapping offers much more than simply taking one piece of data and then mapping it to another ‘pigeon hole’. You can take multiple pieces of data and map them into a single field. This means that the Description (required for IFC and COBie) field for example can be fully automated. Also with the mapping if a user has selected an incorrect Element Classification (i.e. Wall, Window, Door, Furniture etc), the classification can simply be altered (for example from Window to Door) and the data fields will change accordingly.
The creation of the mapping is very simple. Once you have the IFC Scheme Setup open (see image above) simply go to the element on the left hand side that you wish to create the mapping and then choose the required data field. Then on the right hand side simply choose New Rule. You can create multiple rules for each Element or Type. You then move to the Rule Content dialogue box to add the fields you wish to map. There are 3 types of data you can map:
1. General parameters (including data such as Renovation Status, ID, Home Storey, Structural Function, Library Part Name and Dimensional information)
2. Object parameters (any parameter from a GDL object)
3. Static Text (manually inserted text including spaces)
Image: ARCHICAD 18’s IFC Scheme Setup showing a Wall Element’s Description field mapping
The mapping can be created so that it cascades down. So if you want a common piece of data attached to all elements you can create this at the IfcElement level and this will then be applied to every element below it.
The mapping needs to have some careful thought applied. For example, a number of mapping rules need to be created for each tool. The example below shows how a Door Description can be created using the Position, Library Part Name, Width, Height and Static Text (for x, H and Door). The mapping means a user could theoretically use the Window, Corner Window, Object or Other to create a Door. The mapping for these is then slightly different.
Image: Example mapping for a Door Element Description
Image: The mapping for the Door Description (i.e. Interior “Door 18” 1,010.0mm (W) x 2,100.0mm (H) LH Door) shown in the IFC Manager
The work to create the mapping takes a fair bit of thought and also time to go through and set it up. This new functionality has allowed us to automate many of the fields required for COBie (the UK Government data deliverable from 2016) and produce information that can also be used by Cost Consultants and Main Contractors for quantification. Whilst there was a significant amount of time for us to implement the mapping the benefits to the user are they don’t need to manually create data. The time invested to create the mapping will quickly pay off and allows us to ultimately move to being able to produce reliable IFC and COBie for all our projects. Like any new feature there is always room for improvement, so my wish list for more automation and new functionality has already gone off to Graphisoft, however this is a giant step towards reliable open structured data.
More information on how the mapping works can be found in these Graphisoft videos: ARCHICAD 18 New Features: Scheme-Driven Data Management and ARCHICAD 18 New Features: Data Mapping
Also see this blog post by fellow ARCHICAD user Nathan Hildebrandt: IFC Mapping – Why everyone should embrace it
Rob Jackson, Associate Director, Bond Bryan Architects