What Time Has Taught Me

Making a quick Building Information Modeling (BIM) marketing presentation is different from a real design project that involves BIM. And a huge project compared to a normal project is about the same as comparing a normal project to a presentation. A project may be described as huge if its model size exceeds the norm for mainstream projects for reasons such as large area, complex geometry, or an extremely fine level of detailing. Workflow rules change, hardware get more expensive; and add to this the team members’ differing skill levels.

This article shows some lessons learned from a 2.3 million sq. ft. project with a complex, organic shape.

Notes on Workflow

1. Manual versus Automatic

A “happy go lucky” novice design software user, when given two choices—Yes and No—by default always selects Yes, no matter what he’s asked.

What time has taught me: The safe answer is No!

Always reply with “No” to Autodesk® Revit® offers if you do not understand what you are being asked and if you can’t find someone to answer the question for you. For example: Do you want to automatically do this or that…”. Either you or your computer will do extra work. In huge projects, the computer wins and I’ve learned it’s always preferable to do the extra manual work yourself in order to avoid lengthy regeneration times.

2. Worksets versus File Linking

To share a project among a team, worksets are the first thing that comes to our experienced Revit mind,

What time has taught me: In huge projects, linking models might be better, for the following reasons.

  • Worksets are like AutoCAD® layers, meaning users may mistakenly put elements on other worksets. This means periodic maintenance should be run to keep the data segregation.
  • In worksets, all elements are in the same file. In other words, these elements socialize (interact) with each other. Remember the happy-to-lucky  novice guy will reply with “Yes” to the dialog prompt asking: “Do you want to attach intersecting walls to the bottom of the slab?” This causes big trouble. Constraints will erupt here and there, sometimes even without consulting you.
  • Splitting the project to segregated links (Xrefs) by discipline and/or project sector makes it far easier to read, understand, and maintain the project.
  • On the opposite side, cons might include:
  • Any change on families, settings, etc. needs to be applied on more than a file; however, Revit extensions can easily overcome this issue for you.

Figure 1: File linking

Example: The core of a high-rise tower may become three or more standalone files: Core Architecture, Core Structure, and Core MEP, so we can run coordination checks on it very quickly.

3. Splitting Annotation from Model Elements into Separate Files

You don’t need to add an extra 30 to 40 percent in file size to your Revit project, plus thousands of unnecessary drafting elements such as area plans and color fills from the architect.  By the same token, architects also don’t want to see the structural re-enforcement information, and so on. 

As a structural consultant, I’d ask architects to keep their rooms and MEP designers to keep their spaces on their annotation files, because this makes it much faster, especially if they have lots of room warnings.

The benefit to this method is that when you need to coordinate, you receive smaller files.  It also reduces the risk of having unwanted constraints (coming from dimensions and others).  You can look at this way: This is also as a method of sharing the file without the need for central files due to it being much faster to use linking, rather than worksets.

4. Grouping Strategy

Grouping is not only a better practice that decreases file size and makes it easier to change and draft the project, but also, if well organized and documented in a multi-discipline project, it can be reused to create other discipline models. We may replace architectural groups with structural, mechanical, or electrical groups to save a lot of time.

These groups may become pre-fabricated modules in real life.

Documenting groups and passing this bit of information to the contractor is far better for the cycle of information—as opposed to verbally describing what’s similar to what, or what variations exist between different modules.

IPD (Integrated Project Delivery) Truth or Myth?

In a perfect and ideal world “as Autodesk sees it,” as soon as the architect finishes his building mass, he’ll pass it to the structural engineer who will put it on “Structural Generator” (a previous Autodesk Lab application, which is now available in Revit Structures Extensions). Then, using “Project Storm,” the engineer will generate a few options.  He very quickly gives the architect the structural skeleton with some approximate section.  This; however, might not happen for a few reasons, described below.

Figure 2: Structural Generator

BIM Culture

Some old-school engineers still resist BIM partially, or even unconsciously. Some examples include:

1. Who made the analytical model?

  • An architect? Not good for the everlasting cold war between the two professions.
  • A technician? I’ve seen some engineering resistance here, sometimes due to the need for extra training, or for as simple a reason as: “I used to prepare the model on Robot, Etabs … and technicians are only to draft!”

2. Will the design be reviewed on paper or on a computer monitor? Thanks to the economic slowdown, a team of three is supposed to finish what seven used to do.  We have to find more efficient ways to work and that is different than what has been traditionally done for generations.

The last project I worked on was complex in terms of geometry and size. Using traditional methods of submitting plans and sections leaves you with more questions than answers.  As a result I had to train the senior design staff on how to use 3D DWF and Navisworks models, especially the latter, so they could put their comments electronically on the screen (a file to be shared).

This caused a massive change in our workflow and even in the language we used.  We were forced to adopt new nomenclature methods such as referring to elements by their IDs; typing comments on Autodesk® Navisworks® files instead scripting on paper, and so on.

Templates and Contents

The structural skeleton, usually started by architects in pre-concept design, should be modeled using families approved by structures and, more importantly, using a structural template.

The 2.3 million sq. ft. project I referred to earlier was done mainly on Revit, but with some parallel “shadow CAD” tasks; the structural team chose to remodel the architects’ create structural file, instead of modifying it.

  • Technicians wanted to use their template and contents, not something that was given to them by an architect.
  • Structural designers wanted to start from their CAD drawings.

The result: All column and slab element IDs were changed.  This created a very challenging issue when we used the Revit Extensions Compare Model tool. The result was sad to see: All of our previous “architecturally created” elements were deleted! This forced us to track the changes manually.  It was a nightmare.  The situation was so bad that I had to make a plug-in to solve this issue.

Plug-ins to the Rescue

Tracking Changes

As mentioned above, for many reasons, we had to compare two huge models, which had different element IDs and were not copied/monitored. (Note: copy/monitor isn’t so informative in some occasions such as when elements are deleted and new elements are added.)

  • The plug-in I developed will search for elements—for example, structural columns within a given radius of 2 feet. In other words, no matter what element IDs are, it’ll search for the column from file A in file B within a 2 feet radius circle (you can change the search radius).
  • It will then categorize these changes to major, minor, perfect match, deleted, and new, based on a tolerance percentage you choose.
  • Results of this compression are also visual: You can ask the plug-in to put a cloud around each found issue, even create a small call out for it,  and/ or create a 3D cutaway view stamped by date and time.

Figure 3: Smart Compare

Smart Walls by tools4revit

Smart Walls is another creative tool that saves lot of time in a huge project.

  • Let’s say we have a wall in Revit with layers created by an architect. One of these layers is structural and we need to analyze it. This plug-in will separate the wall material layer by layer into different wall segments and make your design workflow far more convenient.
  • Control how walls join, or disallow joints with a pre-defined gap changing as per wall types.
  • Locate center of gravity points (within Revit) or coordinates; renumbering walls in different way.  The tool has many other features that are beneficial to this stage of coordination.

Figure 4: Smart Walls

CAD to Revit

This plug-in converts single-line CAD files into genuine Revit beams or into columns. This can be used as a translator between certain structural analysis software applications that have no convertor to Revit, but can export to .DWG or .DXF.

In addition, it allows you to utilize staff members who use only CAD.  The tools allows for layers/colors to be mapped into a specific Revit family.

Figure 5: Single-line structural frame on CAD

Figure 6: Genuine Revit beams generated from CAD

BIM Model Health Reports

Checking the BIM model’s file health is crucial in huge projects. This is another example where plug-ins can be used. A plug-in can create automated reports showing file size, number of elements, warnings, clashes, number of faces for given category, etc. so the BIM manager quickly flags performance killers.  This is critical when working on massive projects.

Figure 7: Sample of Model Health Check Report


We can sum this article into three main areas that time has taught me while working on some very large projects where Revit was used.

  • Constraints, automatic joints, and other similar element interactions within Revit decrease the performance of your model.  This can become extreme on large projects.
  • New-found skills are required to work within and to manage a huge project within a BIM environment.  These skills and workflows can be transferred to your staff via well-planned training courses and via consulting with experienced Revit BIM managers.  I recommend contacting CAD Training Online (CTO) for instructor-led online classes that are customized to your specific needs.  CTO leverages some of the most BIM experienced architects, engineers, and BIM managers in the world and brings them to your firm via the Internet.  No travel, dramatically reduced costs and training/support on demand are just some of the reasons I recommend their services.
  • Plug-ins can save a lot of time by enhancing the workflow or doing repetitive tasks faster and more accurately.  Take some time to review what I have developed, look at what tools4revit has to offer, and use Google to see what has been released to the public.  Feel free to contact me directly if you need something created to fit a specific need.

Ammar Berrou is a Digital Architect and AEC BIM Solution Provider who provides training and consulting for CAD Training Online. Located in Dubai, Ammar has 12 years experience using Revit on concepts, energy efficient structures, design development, and coordination.  He specializes in multi-discipline design processes, office implementation plans and systems for large and complex projects.  He enjoys going “under the hood” to tailor custom APIs for strategic tasks.  Ammar has worked as BIM manager and has provided training and support in China, Dubai, Middle East, India, and the UK.  Ammar can be reached at

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