What is and how BIM works? Understanding the Concept and its Benefits
BIM is a concept that has been around for over two decades in hopes of helping architects, designers, engineers, contractors and anyone involved in a construction/design project to make their work easier, faster and with less mistakes. First of all, BIM stands for Building Information Modeling and it is used to create a fully 3D model of the project that is connected to a database so that all the information of the project, whether drawings, schedules or text information related to the project, is all in the same place and easily retrieved. This way of working has proven to be quite effective and cost effective and that’s why a lot of companies are switching to it.
There are many BIM programs used in architecture/construction, like Revit, Archicad, Vectorworks, All Plan, and many more, but for the purposes of this article, we will be making reference to Autodesk Revit.
Working on a BIM software has a lot of advantages, some of which we will outline in here:
- Single 3D model: This is one huge advantage of using a BIM program: having a unique 3D model out of which we can extract all the information from. This means that by modeling the project in 3D, we will automatically have the floor plans, elevations, sections, perspective views, schedules, details and any other view that’s required for a project. While creating a 3D model might sound cumbersome for some 3D users, Revit simplifies this process by allowing the user to work in 2D views (floor plans/elevations), but in reality, what we draw in those 2D views are actually 3D objects. Also, the fact that we are building one single 3D model (regardless of the view we create it in) means that any change in any view will update the 3D model and thus all the views that stem from it. For example, a change in the floor plan, will automatically be applied to the elevations, sections, perspectives and any other view, just like a change in a detail or section will update all the other views. Additionally, having the project in 3D allows architects/designers/engineers to understand form better and to detect any issues with the project before it hits the actual construction stage, where simple mistakes can cost a lot of money.
- Efficiency: As mentioned before, the fact that everything is connected through a single 3D model means that the whole process of creating a project is a lot more streamlined. In traditional CAD programs (like AutoCAD), changing something in the floor plan means that we have to make that change manually in all other views where this change is visible. This takes a lot of time and it is quite easy to forget to update certain views (especially when projects change so fast), not to mention that it requires a lot more time to do. In BIM, by not having to worry about updating manually any view (since whatever changes we make are applied automatically to all views regardless of the view we make them in), the efficiency is dramatically increased and the possibility of making errors is also dramatically reduced. A BIM software can be anywhere between 40-60% faster than a general drafting program and most importantly, less prone to mistakes. BIM allows architects, designers, engineers, contractors, etc., to work on bigger, more complex projects or more projects simultaneously, regardless of the size of the studio.
- Parametric modeling: Some BIM software programs like Revit allow the users to create parametric objects. In simple terms, parametrizing means that objects can be connected in different ways so that when a change is made, those objects are still connected and they still work fine. A simple example of this is, for example, is connecting the floor edges to the walls, so that if the walls move around, the shape of the floor updates to follow those walls. This avoids having to manually reshape the floor every time we move a wall. Another example of this is to connect the tops of the walls to the level height. If the height of the project changes, then the wall heights will automatically update to match that new level height. Just like these two examples, there are many more ways to parametrize a project, like setting the position of a door/window in relation to an adjacent wall, distributing objects equally within a space regardless of the size, etc.
- Parametric objects: In Revit, parametric objects are called families, and just like we discussed in the parametric modeling section above, we can also create families that are connected within themselves so that we can adjust their sizes/other parameters when we insert them into a project. Here are a few examples of parametric families:
- Windows/doors: window and door sizes vary a lot in every project. By having a parametric window/door, we will be able to change the width or height of them to match our project needs, this way we don’t have to create a new window/door from scratch every time. Fancier families of windows/doors can be even parametrized to open the window/door, to change the shape of the frame or to add other objects to them (stiles, mullions, etc.)
- Furniture: another great example of parametric families are furniture pieces. Tables, chairs, beds, etc., will all need to be adjusted in different projects. A small space might need a small table, but a larger space might need a larger table. Parametric tables will allow you to adjust the size of them so that they fit your project perfectly. Depending on the furniture family, things other than size can also be modified, for example, in the case of a table with chairs, the shape of the table, the number of chairs, the shape of the chairs, the height of the table and many other things can be changed (as long as the family is configured to do all that).
- Built-in objects: this includes kitchen cabinets, bookshelves and other built-in objects. As mentioned before, each project will be different, so these objects (cabinets, bookshelves, etc.) need to update accordingly. By having a good parametric family of any of these built-in objects, your project will move a lot faster.
- Design: Another feature of some BIM software programs is the ability to design the project in them since they offer tools to explore form quite easily without committing to anything, but to the exploration of form. Once the design is approved and it needs to move to the documentation stage, then the transition from the design to the documentation stage is done seamlessly within the same program. This is a very holistic approach from these programs that most users certainly appreciate. Now, whether fully designing within the software is or is not a good idea is a different topic (we will discuss it in another post), but nevertheless, having the option to do so is definitely a plus.
- Design options: When creating the floor plans of new projects or renovations, clients usually wants to see a few options or wall/furniture/doors/windows arrangements before committing to a final version. Revit comes with a module specifically designed for this purpose, where multiple design options can be created within the same single 3D model. This way, you don’t have to create multiple files or copy the 3D model to the side to explore a different option. Once the client commits to one of the design options, you can automatically update the 3D model to reflect these changes.
- Rendering: While this is not specifically a BIM capability, most BIM programs offer a rendering module to present the project to the client in the form of “images”. Things like the lighting, the materials, the atmosphere, quality, etc., can be set to make the project look alive and photoreal.
- Structural and MEP capabilities: Architectural/design projects will certainly need to go through structural and MEP stages. In the case of Revit, these two are also part of the software, so that everything can be done in the same place. Engineers/contractors can pick up the project and work on their parts while preserving all the BIM functionality and staying in the same software. In case the project needs a design change, this can happen seamlessly since everything is being done withing the BIM software.
- Schedules: As mentioned at the beginning of this article, BIM is basically creating a 3D model and connecting it with a database so that all the information of the project is in the same place. Based on the geometry that is built in 3D, schedules, material take-offs, legends, and other views can be extracted automatically by pressing a few keys. Also, quotes and more thorough reports can be generated in seconds, and this is always using the latest information in the project, which once again, helps to reduce any potential problems and makes the process very streamlined.
- Collaboration: Another big advantage of BIM programs is the ability to collaborate with others, especially in the same office to make sure they are all on the same page and they are working with the most updated project. The traditional setup when working with CAD is that designers draw the floor plans, elevations and sections, and once they are done, they are sent over to the structural/MEP stages so that the next phases of the project can be performed. If this were a linear process, this sounds quite straight forward, but anyone working in architectural projects knows that while the structures are being calculated, changes in the design are also happening, so by the time the new design is sent to the engineers, part or a lot of their work is not usable anymore and they have to make a lot of changes. With the collaboration tools in Revit, everyone is working in the most updated version of the project since it is accessible to all. The minute a change in design is made, the engineers will see it and act on it, which makes things a lot faster and with less re-works.
While these are the most important features of a BIM program, there are certainly more that complement them, and the combo of all these makes these programs quite appealing for any architectural office. In the end, all companies want to maximize their revenue, and BIM programs certainly allow this by reducing mistakes, by working faster, by being able to tackle multiple projects simultaneously, by taking on larger and more complex projects that can be fully visualized in 3D to asses their feasibility, by working collaboratively, etc.