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Macro BIM: When global parameters rule everything

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CAD to micro BIM to macro BIM

As a skilled CAD draftsman, hand-drafting is painfully slow, and as a BIM modeler, CAD is painfully slow, but what makes BIM painfully slow? It is an interesting thought experiment.

The Glory Days of Blueprints <1980s

Glory Days of Blueprints 1980s

The tools for building design have always reflected the available technology. Medieval masons scratched on plaster in their lofts and the modern architectural masters sketch with ink on paper. The glory days of blueprints ended far before I was born in 1991, but alas we are stuck with the word “blueprint” from a chemical reprographic process.

From Hand To Mouse

Introduction of CAD real estate architecture

In the AECO industry, we never fully captured the use of CAD. Many are still manually setting the height of annotations, creating sheets one at a time, or using static blocks or no blocks at all. And now, BIM has emerged. The concept of BIM is simply Building Information Modeling. Take the entire building-worth of information and model it! I asked myself then, as an intern, if “going to BIM” was a good idea. If we could not harness the power of CAD fully, how will we capture BIM fully? As I have learned in the real world, this view is far too pessimistic. Even partial adoption of either of these ideas is better than hand-drafting everything.

From CAD to BIM


Within a single generation, one architect can do the work of an entire team of architects by utilizing BIM. It seems that technology is enabling us to do significantly more with less. The latest innovation is BIM. What most folks use right now is micro BIM. Micro BIM can model EVERYTHING. It holds so much detail that there are even options for it to show you less detail. Micro BIM can tell you how many nails (edit: this is hyperbole- most won’t do this in practice), linear feet of pipe, or number of water closets there are in a 3,000,000 sf building. 

It is very impressive, but attaining accuracy from a BIM model takes a significant amount of investment up-front. The whole building must be built, by hand (mouse?) inside a computer. And just like a real world building, editing this virtual building can become very time consuming. Every object must be modeled, hosted, and placed. It is a painstaking bottom-up process… and for a while is slower at immediate results than CAD.

CAD vs BIM implementation AECO

But what will my generation do? Can we squeeze this process again?

CAD to micro BIM to macro BIM

Macro BIM

Micro BIM has been successful because building a virtual building piece-by-piece is more accurate than drawing a representation of it. Macro BIM is simply BIM from the top-down. Global parameters rule everything. Macro BIM significantly reduces the amount of time spent on design by accurately defining the relationship between micro BIM components.

TestFit and Macro BIM aka BIM from the top down

Here is how to implement it:

Algorithm Architects

This group of people will use macro BIM to efficiently solve micro BIM problems. The lines of code these algorithm architects write up are something more like a design parameter governing all lower-level building components:

  • Ensure all entry doors are within 100′ of a parking space
  • Ensure all units are at least 30 feet deep
  • Provide fire safety stairs in every building area

When several (hundreds?) of these parameters work together we see a real building take shape with macro-BIM. How all of these parameters fight one another for prominence will create friction, but in the end create a symphony. There are few implementations of Macro BIM out there already: Site Ops, Dprofiler, and Residential Engine are a few.

This video gives a brief overview of what macro BIM can do for multifamily buildings.

The long term aim? Generative design. Stay tuned.

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