Wednesday, 14 March 2012

Clarity in the sea of BIM complexity

Many CodeBook users gained their experience using CodeBook with 2D software such as AutoCAD, Microstation etc... and making the transition from 'flatland' to BIM not only requires learning new CAD software, it also requires a fundamental shift in thinking and update in how you use CodeBook.

In this post I'll cover some theory, planning principles, standards and technical elements - hopefully addressing some of the questions surrounding how we used to work in CodeBook 2.5D and how we now work in the BIM world.

Historically 'CodeBook Equipment' would consist of blocks/cells that were linked to the CodeBook library database containing the code, description, group, class and numerous other properties.

Stretching items, such as benchtops, would be driven from CodeBook as would equipment fixing heights. Typically you would 'load' all of the equipment @ FFL and specify the fixing height in CodeBook, so that when you created c-sheets, or room elevations, the front or side elevation of equipment would show the bench at the correct height.

This functionality hasn't really changed in CodeBook, but how this works in the BIM environment vs CAD flatland has changed. We no longer load flat graphical repesentations of equipment @ FFL, instead we load 3-dimensional objects @ the correct fix height, so that they instantly look accurate when viewed in elevation or 3D. Additionally, equipment is often stretched directly within the Revit or Archicad interface by updating parameters / properties.

So what does this mean from a CodeBook perspective? Well, we should still correctly define this information within CodeBook, however the control of these parameters/properties may be driven by the BIM platform and so we need to consider this in how we create our family/GDL objects and also map the fields in CodeBook to the corresponding parameter/properties.

Taking the example of a benchtop, generally you'll have a set number of types based on material, depth and thickness, but the fix height and width will vary from room to room. Within the Revit family, you'll draw an extrusion of the size / shape you require and enable the control of the width (image_1) and fix height (image_2) through assigning a parameter to a dimension and locking to a reference plane.



Recording / controlling these correctly in CodeBook requires mapping these equipment parameters within the project properties > administrator > cad and bim settings (image_3), plus project properties > administrator > define parameter mapping > equipment parameter mapping (image_4)



Configuring and mapping this data ensures that when you link equipment graphics in your library and also update designed equipment from your project, the correct values are recorded within CodeBook. There is another consideration you need to make - do you want to report the stretched size, or default size? In order to report the stretch size, you need to tick the checkbox 'output the sizes of items or stretched sizes from bim to reports' under Equipment library > Details > Options (image_5)


You can control fixing heights through CodeBook, by defining the fix height value in the CodeBook library, constructing your Revit family so that the fix height parameter is locked to the reference plane (top of bench) and mapping this parameter in CodeBook as described above. It is also possible (and perhaps more common practice) to control this in Revit, in which case you should select to 'place equipment blocks with a z height of zero' - which means that the fix height is determined by what you've defined in your Revit family.

Think about it this way - specify the fix height in your Revit family by locking the parameter to the reference plane, specify the fix height value in Revit and tick the 'place equipment block with a z height of zero'. CodeBook then ignores the value it has in the CodeBook Library and uses the default value you've specified in your family.

If you lock the parameter to the reference plane and specify the fix height to be zero in your family, leave the 'place equipment block with a z height of zero' unticked and CodeBook will insert the family using the fix height specified in your CodeBook library.

Controlling such parameters through CodeBook or directly in the BIM platform is a decision each practice needs to make individually - CodeBook can work with this whichever you choose.

Utilizing family types, graphical visibility options and the ability to stretch equipment are all technical Revit family options readily available. Practical considerations relating to modular sized items, construction and procurement though are often forgotten in the sea of BIM complexity. Just because you can embed complex functionality within your Revit families, doesn't necessarily mean that you should.

A classic example of this relates to cabinetry - you could create an adaptive Revit family that allows you to freely adjust the size, shape, material, shelving etc... but this freedom doesn't take into account key construction considerations. Building contractors and cabinet manufacturers will not want to custom make every cupboard on site, rather they will have a stock set of modular sizes they will use and so discreet family types based on these modular sizes is generally the preferred option.

When handing over a BIM model to the client, there is a requirement to have order and structure within the model, so that the procurement, fabrication and installation of equipment and furniture can be managed effectively. This is partly covered by IFC standards and partly by COBie, but the fundamental question you should be asking yourself is what do we need to design, how is it constructed and whether the item in question is a prefabricated modular item that should be based on what is available in the marketplace?

Having FF&E practice standards, based on building code compliance and market availability are where synergies across projects, studios or even geographic regions are gained - which ultimately lead to fewer defects, RFI's and greater profit on jobs.

Clarity of thought, for where Design and Innovation in best focussed and should be applied to projects is common sense that is not always common knowledge.

Understanding the downstream requirements of the contractor and client are considerations that need to be applied during the design phase, software doesn't do this for you. The "BIM enlightened" integrate these considerations early on, so that software can make the documentation and scheduling of complex building easier.

Make it happen...