The problem with IFC

There is a sudden increase in talk around IFC in the industry, and annoyinly there is a lot of miss infomation and lack of understanding of IFC and its use.

What is IFC and where did it originate?

IFC stands for Industry Foundation Class and It is intended to be a platform neutral exchange format for both geometry and its embedded data.

IFC was originally created by AutoDesk in 1994, when they formed an industry consortium to develop some C++ classes for integrated application development. This consortium opened its membership to all open parties in 1995.  In 1997 the consortium was re structred as a non profit organization with the goal of creating a standard for a platform neutral AEC model for building lifecycle, the IFC format is now managed and developed by BuildingSMART.

Over the last decade or so there have been many variations of IFC with the latest been IFC2x3.  Standards for IFC2x4 was issued for comment in October 2011, and will be known as IFC4 and almost all cad/BIM software now has export to IFC functionality.

Whats wrong with IFC?

Basically it's shite. While I agree with the openBIM concept IFC is currently not a reliable solution for BIM content, model authoring or data exchange. It can (if done properly) be used for a static as-built record Information, but even when used for this purpose validation of the data is critical.

Problem 1 - Data Loss IFC has a horrible habit of losing information or dropping data when exporting from its native format.  The extent of data loss varies from software to software and has improved in IFC2x3, however ANY data loss in a construction model is a major problem, especially when this single model will be used for many applications from clash detection to structural analysis etc.

The Native file showing the Steel Channel

The same file exported to IFC and imported into Navisworks for coordanation with the other consultants BIM, notice how the steel chanel is missing.

So why is this data loss happening? If we look at how an IFC exporter works, we begin to see the problem.  Firstly the exporter will dump all the geometry into the IFC along with the data, both of which are tightly interlinked. If we think of how a typical BIM model is created, its has many fields each containing data.  Some of these fields, such as project name, location etc are hard-wired(and easy to map between software packages), however a typical BIM will have many user created parameters unique to that BIM. Upon export these fields and data are assigned a pigeonhole (location) in the IFC file.  The problem is that currently the different software vendors map these fields slightly different upon export. In REVIT the pigeonhole for 'column top level' might be In pigeonhole no1, however in Archicad the 'column top level' data would be placed in pigeonhole 2 etc.  So if Revit reads an IFC created in Archicad we get data loss or incorrect geometry.

A structural colum from an IFC structural model.

Circular Holes in a Structural Wall Imported in an IFC, are corrupt and display in wrong location.

 
Problem 2 - Another fundamental problem with IFC is that it doesn't currently support all the clever time saving parametric stuff that we expect from BIM components these days. IFC is all about the geometry and data and upon export it normally dumbs it down to just that.  An example below shows a native toilet cubicle component made in Revit, which uses formula with parametric capabilities to place a transparent pink cube around the component if the user tries to specify a component larger than the manufacturer allows. However when we export this component to IFC this cube is placed in the IFC(along with lots of other things that should be hidden), and we lose all our clever parameters and formula and we have everything showing.

	Image 1 - A Native Revit Component.
	Image 2 - The same componnet when opened from IFC.

 

How can this be fixed?

At first it's easy to say let's all agree a common standard(openBIM) that all the major software vendors support. However there are a few challenges to overcome:

• Every building is unique and the Type of embedded data will vary, with a lot of custom parameters added by various people at various stages for different reasons. When it comes to mapping these unknown parameters what will the receiving software package put them and will it be where the exporting software package intended?

 

•  Different parametric engines in the native software packages causes headaches (as shown in the cubicle example above).  What we need is a IFC standard that supports parametrics.  Problem is every software uses a Diffrent formula & parametric engine, so creating universal parametric language would be required, and this would always be limited by the weakest engine in the various native software package (to ensure compatibility), meaning the component is never as good as the original native component.  Add onto this that each vendor is constantly making changes and adding new features to the native packages, it adds another layer of complexity into developing a platform indipendant open standard.

 

Problem 3 - The third problem is miss-understanding of what IFC actually is.  One of the larger BIM software packages nativley supports parametric IFC content, however this is a IFC file format unique to that particular package, and when opened into anything but that package we get the same basic IFC without the parametric or material data etc.  The problem is if you have been using that software for quite a while, without broader knowledge of IFC or other software then your opinion of IFC is that it's Awesome, and a solution to all the problems, which in reality isnt the case in a collabrative enviroment.

While I really hope that a we will all get platform neutral exchange format that works, I really can not see how the future of IFC can develop to overcome some of the challenges it faces (at least in the next 5 years). The biggest barrier in my opinion is that no matter how good IFC becomes, it will never be as good or have the functionality as the native BIM package it was created in. 

It annoys me when I see new BIM users (most of the time without software experience) shouting about how we must all adopt IFC & openBIM now-today, because on the outside it looks like a perfect solution, when infact its actally a load of work arounds.


Before I get slammed for IFC bashing, I want to make it clear that i DO support the OpenBIM concept, and I think IFC is a suitable deliverable format for record purposes (as a static model with data embedded on completion), but for delivering BIM components - It just does not work at the moment.

I have seem people refere to the problem of BIM transfer standards the same as the HTML problem 10 years ago, however HTML standards are actually quite straight forward.  Its a set of standards for doing nothing more than displaying images and text in a browser window (the clever dynamic stuff is done by a load od other technologies that plug into html, such as PHP, ASP, Flash & Javascript etc - some of which are proprietory).  The problem with BIM is that there are so many uses the data can be used for such as coordanation, visulization, energy analysis, cost analysis, facilities managment, simulation, 4D, 5D and more things that are developing every day.

BIM is about doing things better, and more efficiently while reducing cost and unfortunately all the IFC workflows i have tried do not support this and normally requires checking and rework.


To prove my point, I'll set a VERY basic challenge:

Email me an IFC file that I can load as a door component in Autodesk Revit and insert into the wall below.  I want to do the following basic things with it. Change it's heigh & width, toggle it's level of detail to show door handles, and have an attached render material so i can render it.  Surely this isnt too much to ask?



I really hope I get proved wrong, and if I do I'll give a trophy in the form of the now legendary bimstore.co.uk "I heart BIM" mug.

Category: Parametric Pervert

Im back! A quick update..

It's been ages since my last blog post, this is for many reasons. Trying to find time to sit down and blog my thoughts and ideas has kind of taken a back seat, but I'm back and intend to post a blog at least once a month. So what have I been doing? Well late last year, I become a proud dad to Brodie Ward, my rather awesome daughter. She is definitely one of the most parametric families I have ever made and has been keeping ;me more than busy.

Below are some of the more interesting things ive been working on in the last 6 months, I thought id give you a quick update before blogging resumes as normal:

_spacehus

I've also been working on a few interesting projects lately also, some of which I can talk about and some which I can't (yet!). One of these projects is the spacehus.  The spacehus, is a product we (spacegroup) have been researching and developing for the last 10 years, but recently with the current economic climate and sustainability at the top of the agenda, it has propelled it from a concept into reality.

The house itself is a modular sweedish timber framed kit, pre-plumbed, pre-wired and pre-finished off site using just 19 standardised modules that is more like assembling an airfix kit than a house but make possible a 20 day construction period. The house is also a code 4/5 (upgradable to code 6) sustainable, meaning it's power usage is less that £10 a month and with the 3 bed version at just £80,000, it's affordable.

                       

 

You are probably thinking that this blog is starting to sound like a big sales pitch for the www.spacehus.co.uk, and you would be right, but I'm leading onto something that makes it all relevant to this blog.

We are well down the road with BIM at spacegroup, and our CEO Rob, set me the challenge of using the technology and knowledge we have in designing big multi-million pound projects into designing a small sub £80,000 house. His brief was:
      -Code 4 sustainable, minimum.
      -Design to Handover in less than 4 weeks.
      -Full component based fabrication drawings from the model Inc cutting schedules.
      -Paperless delivery I.e no assembly drawings on site - iPads?
      -Flexible design variations from the single model.

Before I go on on how we went about achieving this, it's worth noting that there is a lot more to the spacehus process than just a super parametric BIM model, for example we knew that we couldn't use the normal uk construction methods to construct the house (up to 8 different trades, all on site bashing things together from raw materials) so each house is built by a 5 man _space build team who are trained to do everything, electrics, plumbing, joiner, even operating the crane that lifts each module into position. Anyway back to BIM.

The Aerospace process

 

The _spacehus process

The first challenge was easy, we used tools such as ecotec, green building studio and a bunch of other cool bits of software to prove it's performance, all based of a Revit BIM model. This process continues and we check every space houses design is optimised for it's and location using autodesks 'green building studio' which pulls local data from the nearest weather station then performs analysis to see what can be improved. We can also run various options from the same model to optimise the design, we call this optioneiring.

           

 

The second challenge was quite a bit harder and involved building a Revit model so complex and intelligent that it could produce not only component and assembly drawings but also fabrication drawings and cutting schedules, down to every nut, bolt and screw. Not only did it have to be detailed, the model also needed to be super parametric, to allow changes and multiple variation easily. I.e. - if we stretch the rear wall back by 1m all the associated components will adjust accordingly based of a set of pre-defined rules and formulae. All joists will increase to suit there span, and additional studs are added automatically. All while ensuring the model can't be changed to something that won't work or be impractical (panel that won't fit on the back of a truck etc). Normally over modelling is bad in any BIM model, but because of the repetitive use and nature of this model, we could spend more time on the initial model, meaning any variations pulled from this model are created almost instantly including all fabrication info and because of the small size, we are confident of no performance and file size issues.

         

        

 

Over the next few blog posts I am going to focus on how we built this model and some of the parametric formulae that drive it. Hopefully you will find some of this useful in your own projects.

Planning is the most important part of Building any BIM model, you need to know what you want the model to do, not only now but well into the future.  Before we started modelling the first thing I did was use mind mapping software to break each component down, to it's basic parts (the 'stuff' we needed to record and schedule). Because of the fabrication process this was critical, as we needed to extract as much data as possible, such as every timber stud length, size and end cut angles etc. The tree above shows the first initial attempt at this for one of the 19 standard spacehus panels. Every branch is a parameter that we need to schedule. By using mind mapping software, it let's us visualise easily everything and see there relationships swell as the important assemblies, sub assemblies and component
parts.

   

We have shown the _spacehus BIM model and the BIGBIM concept at various user groups and events, keep an eye on this blog for future events. I will go into some of the advanced parametric's, rules and formulae in a future blog post, starting with the Intelligent self sizing and self checking joist component.

 

bimstore

Another project I have been heavily involved with since my last post is bimstore.co.uk. We have created a whole website and distribution portal for manufactures to host there BIM components, giving them a shop window for there products. We like to think of it as iTunes for BIM components and are hoping it becomes the UKs no 1 place for quality BIM objects.

            

One of bimstores strongest features, is that all content is made to the same high consistent standards, regardless of manufacturer, this is backed up by our family creation standards document, which we are calling the 'Bimstore Bible' which can be downloaded from the site. We are really proud of bimstore, so check out the site push any manufactures our way, and we will set the 'BIM Geek' onto them!

BIM Technologies

We are gearing up to launch 'BIM Technologies' side of the business and are already working on various projects. BIM technologies consists of some of _space groups top BIM minds, joining forces to solve challenging problems. BIM Technologies, can do everything from build  a fully coordanated BIM model using our BIGBIM approach, to full digital design and fabrication processes.

For example, we had a project, where both the architect and cladding manufacturer could not produce fabrication or setting out drawings for a rather 'funky' freeform cladding system, and even if they could the form was too complex and every panel would be unique and costly and it would take weeks using traditional processes.  What we did was take the architects concept and ideas, and in less than a week produce a fully co-ordinated model and optimising the number of panels, cutting the total unique amount of panels in half. We then provided the manufacturer with a set of fabrication drawings for each panel as well as providing inventor part files that could be used by the CNC cutting machines, a process that saved further work.

          

     

I will post more on BIM Technologies when the website goes live, in the next few weeks, but if there is anything you would like us to look at drop me an email.

The above is a quick overview of what I have been up to in the last 6 months or so before I went AWOL on my blog. I will fill you in on the rest in future blog posts.

 

 

Category: Parametric Pervert

Parametric Arrays & Reporting Parameters explained

I posted this video in the 'Tutorial' section of the site a few month ago, but thought I would share it with my blog followers.  Remember to sign into revitspace for more tutorials like this one.

How to create parametric arrays is one of the questions I am always getting asked in our office, and they are quite simple whey you understand the little tricks that make them work. The video below shows a parametric array in a curtain wall panel, and also does a good job of describing how the 'reporting parameter' works.

From my tutorial:

 

"Revit 2011 has a new 'Reporting Parameter' feature that allows families to use (report) Parameters from its host family.  This can be used for simple things like allowing scheduling of wall host widths in a door schedule to much more advanced Formula driven components and conceptual components.

Another use for this feature is in curtain walling.  We can now create a parametric louvre panel that is adjustable to its host.  This means if the curatin wall is changed in the project, then the louvre panel will update, adding or removing additional louvres as required etc.  This was not previously possible in versions prior to Revit 2011."

 

 

 

To demonstrate the process used including creating a parametric array, see the video tutorial below. You can download the finished family HERE.

 

 

Category: Parametric Pervert