AC21 - specifications

[alemanda]

Hi to all.
I would like to have your suggestions on how to manage specifications (according to Masterformat) in AC21.
Is it better to define a set of properties or build a classification system? Or combine the two?
What are the advantages of using the first rather the 2nd once?
Classification system is more limited?
What about the translation to IFC file for sharing?
What are the limits in the schedule arranging?

[Tim Ball]

I have set up my whole specification using customised properties. So I have specification notes embedded in every element, object and some 2D icon objects where its just text needed. All of course linked to favourites.

The properties information is accessible to labels, schedules and in the BIMX info button.

It works really well for me, and whilst it does take time to set up, once you have it running its a real time saver. I am running a course that deals with just this kind of advanced use with Eric Bobrow at the moment, just search for Masters Of Archicad. There is a video giving an outline on my practice website http://www.jhdarchitects.co.uk/building-information-modelling-bim/3d-design-client-benefits/

If you want to export the properties to IFC, you can edit the export translator to include properties as image attached

[alemanda]

So you use properties and not classification. Right?

[Tim Ball]

You really need to use both.

Basic classification gets you to the right starting point for setting up the properties. If you need to output fully compliant IFC files, which I don't need to do, then you need to follow the full classification system applicable to your projects. That should be driven by your clients needs.

However classification doesn't include the kind of specification information I need for my projects. Whilst many people think the specification belongs outside the model, given that AC is really just a database with a nice 3D interface, why not use it to its full advantage.

[alemanda]

Tim wrote:
...
Whilst many people think the specification belongs outside the model, given that AC is really just a database with a nice 3D interface, why not use it to its full advantage.

I agree 100%

Before, in AC19, I set up a "classification system" using IFC properties so I had my specifications (I use masterformat for my projects abroad) fully coordinated with each element (or groups of elements) of my BIM model.
Using IFC mapping I've been able to have a also a fully coordinated BOQ.

Now I passed to AC21 and I was testing classification systems and properties also to understand which of the two systems is more smooth.

What I like of calssification system is the ability to choose from a preset list. This cannot be done with properties.
On the other hand, with properties you are more free to add the parameters you need in order to build the schedule. For example it would be possible to have chapters (materials, submittals, preparation, execution, etc) in single properties so that by IFC mapping you can "mount" together them in order to get the full text of the specification.

[alemanda]

IFC properties, in case of medium size propject (for me around 150 MByte), are not so fast to handle.
That's why I would like to change.
Can I expect properties to be handled much faster?

[Tim Ball]

You get the same in 21. I find both properties ad IFc are faster in 21, indeed with each release.

Don't forget that you can pick from a lost in properties as well. You can set a field with your own list to pick from