BIM Principles

BIM or Building Information Model is an important acronym these days. Its principles are simple but often misunderstood. I am going to share a few ideas that make a huge difference when practicing CAD (Computer Aided Design). I am using simple language for an easier understanding. I will be updating this page regularly.


First of all CAD really does not make anybody a good designer. First mistake is to think that a computer makes you reach your design goals. Design and concept development takes place in the real world where the artist does something with his/her own hands to create a sculpture, model or a drawing. The result that has the artists personal touch included is then taken into the digital world to develop a digital version of it preserving the artistic qualities as well as possible. Stylus pens come close to the performance of a real pencil/pen but are not there yet. 3D sculpting gloves or similar might be the future. If the designing phase is started with Revit or other 3D software it will never be truly your creation. The constraints of the software might affect the design.


However, after the original idea/concept is made digital the Computer Aided Design development starts. The first thing to determine is what level of detail is necessary.


There are two levels of detail: Competition/Concept Level and BIM Level


Competition/Concept level

Basically the idea is to develop as low detail model as possible. To do as little amount of work as possible. Architectural competitions are basically zero profit work for firms as you can catch the big fish but you cannot count on it. The same applies for concept development where it is important to visualize the idea of the project but you should not spend too much time on it because the client might not like that specific idea.


  • Don't model everything. Figure out the views you are going to show and make a quick 3D model focusing only on the things that are visible

  • Model perfectly only in the places that are the closest to the camera. A good 3D detail looks pleasing but dont waste time in the small details that can be photoshopped later.

  • Use Illustrator for fixing errors in drawings. 

  • Don't use this model as the template for later phases, start over.




BIM Level

Once the project actually starts the principles take a 180 degree turn. Now we are building a actual 3D building. The 3D model needs to represent the real life as close as possible. 


In a perfect world a perfect designer will use one single software for everything (I am talking about the workflow of an architect only). No SketchUp to Rhino to 3dsmax to Revit or similar workflows. Just the BIM software is used. Revit and Archicad both offer excellent predesign, (freeform modeling in Revit) and rendering possibilities (Take a look at my "Carving" work staircase picture. It is Revit only.) The advantages are that it is cheaper to have less software licenses, software understands the shape and can calculate materials and the workflow is faster.


Revit and Archicad basically share the same principles but they operate differently. First thing always is to setup the file. 


  • Setup locations, create topography (not too detailed as it will slow down the computer), all of the project details, start the final CD sheets and assign basic views in them. Create floor levels and basic sections. When this phase is done first and is done well the amount of last minute work is greatly reduced and you'll be able to respond to quick drawing requests fast. Organize everything first before jumping into modeling. Create a project template that you can use later to save time. 

  • Start modeling walls, columns, roofs and slabs using the right tools (wall tool for walls etc.) If you use for example slab tool to create something else make sure to change the properties so that the computer knows what it really is.

  • Use all of the components and features the software offers. Don't be afraid of trying new things as all of the features are there to be used. Just let others in the firm know what you did.

  • Don't create 2D data unless necessary. The more 2D data the model includes the slower the workflow will become. Drawings will not update automatically if the data is 2D.

  • Avoid too much detail. If you put 1000 very detailed wide flanges on the model it will become slow. In large projects a rectangular shape beam can be used to represent a wide flange as long as the properties are updated. In the detail drawings 2D component can then show the real shape, but remember to group the objects to update the drawings automatically. Site topography and foliage, trees etc. make the model very slow. Once the topography is modeled and the final position of the project is established the topography can be backupped to another file and deleted. Trees and such can just be 2D components and for the renderings it is faster to just photoshop them in.

  • If you have worked with Revit or Archicad for years, update your workflow. Read about the new features and use them. You can use your old way of doing things but it will most likely be slower and the data might not be as accurate as it can be.

  • Clean your model regularly. Make sure that there are no duplicate items or old material that is not needed anymore.

  • Establish your own BIM principles. Talk with your teammates and figure out rules for workflows.



More to come...