Building Something Before It’s Constructed


So now that we’ve had a few posts explaining the collaboration between the Architect, Owner and Contractor and have been jumping around to different points in the timeline. Like a Tarantino film, we are now going to completely jump back in time all the way to the beginning. Before the drawings are even created an Existing Conditions Model needs to be created, which we are going to walk through today. I am proud to present the fifth post for the Video + Blog series “What the Hell is Architecture?” A series that will present Case Studies, Code Commentaries, How-To Videos, and anything else that comes to mind to try and get the word out on what Architecture, Engineering and Construction ACTUALLY is. (Something the industry has done a poor job of enlightening the public on.)

This week we are going to tackle another time-consuming task Architects must take, documenting the Existing Conditions of a building or site. According to the AIA, (American Institute of Architects) in 2018 roughly 44% of Construction and Design was dedicated to the improving or Rehabilitation of existing buildings. This tends to be a lower percentage when the economy is “good” as people build more new buildings, but as the economy is cyclical and will decline, this percentage will then rise. The takeaway from that statistic, a large percentage of our projects require exact documentation of existing buildings. (If Contractors don’t have a clear idea of where or what they are working on, the bids will only skyrocket in price.)

The Argument for BIM Modeling Over Lines

First off, whenever Architects discuss new technologies, they tend to throw around Acronyms without realizing how off putting that can be. Below is a list of the acronyms used in this post.

  • VR – Virtual Reality
  • AR – Augmented Reality
  • BIM – Building Information Modeling
  • CAD – Computer Aided Design (2D Drafting)

Second, not every Architect uses 3D or BIM modeling. I personally have worked on many large projects that were done solely in 2D CAD linework. However, after years of working in both formats I can confidently state (as well as provide data on amount of man hours required for each) that creating a BIM model is the best way for your project’s success. I’ve had many heated debates with other Architects on whether it takes too much time to build these models, but every project had the same conclusion…Building a detailed model upfront may take a little more time than drawing it, but it will save significant time in all future phases of the project, as well as allowing much better collaboration between all parties, thus saving significant time and money.

What is BIM? And Why Should an Architect Build It?

So why do we keep calling it a BIM Model instead of just saying 3D? Because a 3D model is simply masses that make up a shape or model, A BIM model is a model with Building Information built into it. When we create walls, we aren’t just making masses that resemble the size of a wall, we are building the walls with the actual building materials and placing them in the model. (Wall Finish, Stud Thicknesses, Insulation, Etc.) This distinction also brings up another discussion that sadly happens often…Why would a client hire an Architect to build a BIM Model when plenty of companies offer services of modeling an existing space? Because you aren’t just looking for a model that looks like your building, you need a model that contains all the construction information needed for a contractor to start working on your building.

I must ascend my soapbox for a moment here, building a perfect model is not possible, however I have worked on many projects where the Existing drawings or models have been given to us from others. While they did offer a great starting point, I have never once been able to continue the project without visiting the site and adjusting/fixing the drawing or models either, thus furthering my point of why an Architect should be putting together these drawings or models, because they are still going to have to do it anyways and bill their time for it.

Creating the Model

We are going to break down the modeling effort into three phases, listed below. We will break up this post into two parts.

  • Exterior Shell of Building
    • Walls, Roofs, Windows, Doors, Materials of Building, Etc.
  • Site Elements Around Building
    • Neighboring Masses, Ancillary Buildings, Landscaping, Topography, Etc.
  • Interior Environment of Building
    • Casework, Furniture, Flooring, Etc.

To demonstrate the process of building a BIM model, we will walk through the process with a building I have visited quite a few times. This post is going to be broken up into two parts, Part 1 will be the discussion of building the Exterior Shell and parts of the Site Elements. Part 2 will be finishing the Site, and fully modeling the Interior Environment. For anyone who reads both posts, the second post will also have a Virtual Reality application of the model uploaded for anyone to view on their computers, with or without headsets. (If you wanted to cheat, you could just read the Second Post to get the model.)

From Survey to Scale and Massing

Now that the really long preamble is over, we can finally start building our model. The first document we start with is the survey. A survey is the documentation of a property, performed by a licensed Land Surveyor, that will document multiple items needed for your project: Property Lines, Dimensions of Buildings, Locations of Utilities, Topographic Contours, Etc.) Below is an image of the Survey I used for this project. (With all the legal items and firm names removed.)

Survey of Property

From this we are able to create the massing for our building, front porch, back porch and garage. We are also able to place fencing and the property lines and the preliminary boundaries of the different surfaces. (Grass, Gravel, Asphalt, Etc.) We also begin to set our Building Levels at this phase, which you can see in the images below, more on that later though.

Front Porch, Garage and Building Massing
Back Porch and Fencing Massing

Building the Interior Shell

First Floor Plan – Walls and Partitions
Second Floor Plan – Walls and Partitions

Building the Neighborhood

So now that we’ve fine-tuned the layout of each floor, we not only adjust our building model, but we also start to model the surrounding neighborhood. This may seem like extra work, but too many Virtual Reality models have a building floating in space, when in reality that is not the case, there is also surrounding structures, landscaping, etc. You’ll notice the buildings not on our property are very vague masses, we can assume that each story is roughly 8-10 feet, and the general shape is all we need. (I have been chased off enough properties to advise that while tempting to take measurements and photos of neighboring properties, you shouldn’t do it.) We also begin to start creating our building’s roofs.

Massing the Neighbors and Adding Roofs
Massing of Driveways and Garages

Fenestration (Doors and Windows for the Less Pretentious)

Now that we have the layout, roofs, and site modeled we are missing a key component of our building…The doors and windows. We will measure and model all the interior and exterior doors, windows, and openings. An important thing to consider that while it is tempting to model everything perfectly, the reality is a lot of the windows on this house do not align and have different sill heights. (Something that drives me crazy every time I am here) This is also when we start adding the materials of the house, in this case the house is cladded with yellow Vinyl slats.

Adding Doors, Windows and Exterior Materials
Adding Doors, Windows and Exterior Materials

The Vertical Access Shaft (It’s the Stairs)

A big challenge when measuring and photographing these sites is trying to get all the heights. Sadly, due to dwindling budgets, there is usually only one Architect crawling around the site documenting it. After touring an abandoned residential building where the homeless population were clearly living in, I will advocate every day that no matter the project, there needs to be two people documenting the site. But we’ll save that rant for another day and get back to the post. This is where we have to get creative. I was able to determine all the heights based on the following items.

  • The stairs are an opening between both floors, allowing the chance to measure the height between the ground floor and the second-floor ceiling. (Right now, we simply need the general size of the stairs, detail will come in a later phase)
  • The windows and doors will allow the chance to check that the Exterior looks correct. (You can see in the previous images, that the initial roof locations are incorrect based on the windows colliding with them)
  • Perhaps the least sophisticated, yet most tried and true method…Simply measuring the exterior material and then counting how many are in the building façade. I determined the Vinyl Slats are 8 inches tall, and then stood in the driveway and counted them. (In front of the neighbors.)
Stairwell From Basement to Attic Floor

The Final Details

Now that everything is starting to get buttoned up, we finish with the last few details. We readjust some roof lines and pitches, as well as adding the Roof Fascia and Soffit Boards. The Vinyl Siding is also raised above grade, with Brick and Concrete foundation walls below. (Commonly known as a water table, as most materials don’t do well when in contact with standing water) With all this, we finally have our Exterior shell for our building, ready for all the Interior details to be placed.

Our Exterior Shell of the Building
The Actual Building We Are “Building”

Coming Up On Next Week’s Episode

While we have started with some baseline site elements, there is still some editing to be done. No site on the planet is perfectly flat, and this site in particular has some significant elevation changes. There is also landscaping to create, more detail on the back porch is needed, and sadly none of the fences are in as great condition as shown in the model.

We also tackle all the interior details for the house with the ultimate goal of being able to navigate around the Virtual model as if it were a video game. (Both a Headset and non-Headset application will be uploaded to the website for anyone who wants to tour the house and critique any of the furniture choices.)


BIM and Virtual Reality modeling offer endless advantages in this field. This post has been slanted towards documenting Existing conditions, however it is as invaluable for New Construction as well. A project may have an Architect, Structural Engineer, Plumbing Engineer, Mechanical Engineer, Electrical Engineer, and many others all designing at the same time. If all are building BIM models and linking each model, then many design corrections and decisions can be made much cheaper. A Pipe running across an open Stairwell is infinitely better to discover while everyone is designing and modeling, as opposed to after the pipe has been installed on the job site.

No matter the size of your project, whether it is a New Build or Construction in an Existing Building, having an Architect prepare a detailed model ahead of time will save COUNTLESS hours in subsequent phases of the project.

Virtual Reality itself is the logical next step for BIM modeling. Many who don’t spend ten hours a day looking at Floor Plans or Sections can’t gain the same amount of understanding when looking at them as those of us in the field might. A rendering or image of the space can help someone understand, but true understanding of a proposed design comes from the “experience” of moving through it. This is no coincidence to the amount of rendered video walkthroughs that have been on the rise over the years, however even these pales in comparison to the sense of putting on a headset and literally walking through the building as if it were built.

My final pitch for BIM and VR modeling is simply this, if created correctly, the model that is created can not only be used for Virtual Reality and for 3D modeling of the space, it can also be used to create the Construction Drawings. Stated even simpler, building a model upfront provides more communication to all users, creates much better drawings, is done much faster, and for much cheaper.

If you feel I missed the mark or am misinformed on any aspect of what I wrote, please let me know. If you caught the American Dad quote in this post, bonus points for you and let me know.

If you did enjoy the post or have any ideas or questions you would like to see or hear about in the upcoming posts and videos in this series, please let me know that as well.

Thank you all and have a great day.

  • Bryan Toepfer, AIA, NCARB, CAPM
  • Principal – Architect

Lets Build Something Together

Bryan Toepfer, AIA, NCARB, CAPM
Bryan Toepfer, AIA, NCARB, CAPM

Bryan Toepfer is the Principal Architect and founder of TOEPFER Architecture, PLLC, an Architecture firm specializing in Residential Design, Construction and Virtual Reality modeling.

Taking his philosophy of the importance of education to heart, he guide clients through the process of Design and Construction with each project. He runs a blog titled “What the Hell is Architecture?” with the goal of sharing with others the many aspects of Architecture. He also coaches Intern Architects studying for their Architectural License exams, as well as teaches at a local University.

He lives in Rochester, New York with his wife, two dogs and two cats.

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