Friday 22 March 2013

London Revit User Group – Post 2/2

"Just one more question"
We’re hugely grateful for a chance to speak to some of the most influential and knowledgeable BIM professionals in “the capital” at the London Revit User Group. Last year on the same bill as Paul Morrell and then again this year at a special session with us as the lead speaker.

The unwritten rule however is that the LRUG top-brass have their annual chance to ask me the hardest questions they can think of at the end of the session. Strangely enough, this is pretty enjoyable, a really good challenge and it proves for an interesting debate. So here is the pick of the questions from Mssrs Wooldridge, Light, Collins and Oakley… and my answers...

1. Can you please speed up your content creation programme?
We’d always like to do more. But I think we’ve done pretty well in the first 12 months. We’ve had three major releases of generic content, each with about 150 objects in. We’ve also very quickly took the number of manufacturer objects up to around 150 objects. So now we have around 600 objects in total.

What makes this a more time-consuming process is that we take great care in defining the property sets, functional parameters and providing consistency across all objects (so for example, FireRating is the same for walls, partitions, doors, generic and manufacturer objects).

And the majority of objects are in many BIM vendor formats – something pretty unique to National BIM Library. So if we counted all of these objects separately there are more than 2,000 objects.

We could accelerate the programme by charging for the objects and using this money to pay for faster content development. But the business model we have gone for is to make this content free-to-the-industry. Our feedback to date is that this is definitely the correct approach.

In the next twelve months we are looking to match our building fabric content with a similar number of objects for service engineers. Manufacturers are also joining the service on a weekly basis and we have another nine manufacturers in the pipeline with content coming online soon.

2. On large projects, teams aren’t going to associate every object against an NBS specification. Would you agree this is too much effort?
The more savvy practices will associate their office master objects once and then they won’t have to associate every object on every project. They just need to do this once centrally for their “toolkit of objects”.
Consider a fictional practice called ABC Design that has a collection of system and family objects. All they need to do is to create a few template jobs with these items in, then use the NBS toolbar to stamp the correct references in. The screenshots below demonstrate this process.
A template job and a template spec are created
Each object is associated with its corresponding spec
The toolbar functionality stamps these parameters and values into the objects
This of course could be done in the traditional way in the Family Editor or Manage tab using the National BIM Library shared parameter file (included in all Revit downloads).

3. Doesn’t co-ordination all fall down if you aren’t coordinating the information inside the objects?
We can never solve all coordination issues. But what we can do is improve things step by step. Our tactics here have been to link databases first, and then objects second – the natural progressing here is to help coordinate the key property sets. We are looking into this now in our R+D team.

However, this is not a new issue. Twenty years ago someone could write “60 minutes fire door” on a drawing on the drawing board and type “90 minutes fire door” in the specification on the typewriter. So practices have always needed to have an office policy in terms of what information goes where.

In the examples below – where certain information goes is reasonably straight forward. Geometry would go in the geometric model for the main objects. A lot of other information (such as the evidence of compliance in the example below) would go in the specification model. The tricky one is the fire rating example. The master specification system has detailed guidance, links to standards and regulations and suggested values.  However, the geometric BIM software has fantastic visualisation performance analysis and instance scheduling functionality.

So this is the hundred million dollar question.

What is the answer?
Where do you put the information?
My personal view here is that, firstly, consistency between these key shared property sets is needed. This is where IFC comes in (or maybe more precisely perhaps IFD/Data Dictionary) – unique ids need to connect this information – whether between spec and drawings – or whether this is a language translation from English to German.

The user should be presented with three options:

  • Option 1 – the spec is the master and the geometric model is the slave
  • Option 2 – the geometric model is the master and the spec is the slave
  • Option 3 – neither is the master – the user is alerted to coordination issues and they then make an informed choice

This may sound like a pipe dream – but I don’t think we’re that far away. The screenshot below shows the IFC demo I went through at LRUG. The IFC model has merged information from Revit and NBS Create. The FireRating below has actually come from the specification. Through shared mappings it is possible to coordinate at a level below the object itself.

The value of "99" came from the spec - not the Revit model - inserted directly into the IFC
So, going back to the question (at the end of a long answer) – I think we have to look at how full a glass is and not how empty it is.

4. Why does your wall library not include existing Victorian walls for alteration jobs?
We’re straying into detailed content development questions here (which is not my area). But I *think* we made an initial decision here that:

  1. A. On most alteration jobs you would simply model the existing building as concept objects – for example, “a 300mm wall” and not go to the level where you model the materials within a Victorian wall.
  2. B. By providing detailed documentation on our naming conventions and materials – practices can use the National BIM Library principles to expand our library of 70-80 wall constructions and configure their own.
But, by all means, keep the content questions coming in to or our linkedin site and we’ll target our efforts at where the biggest demand is.

5. At an early stage of a project we don’t know details – so how can we spec the items?
National BIM Library can be used from a very early stage on a project. Most systems have concept objects (say 300mm walls or flexible doors and windows). At this concept stage – NBS Create and links to the spec doesn’t really come into play.

NBS Create begins when the early spec decisions are made – for example, the floor is likely to be timber boards or the roof is likely to be clay tiles.

At this stage, the National BIM Library concept objects can be swapped for the more detailed objects and the NBS Create outline specification can be created.

So, some pretty tough questions, especially for 8.30pm on a Thursday evening. But this is the sort of BIM debate we need. In my opinion, it beats a Powerpoint slide show of the BIM-triangle and BIM-circle-of-life any day of the week.

I look forward to 12 months’ time to do it all again.

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