CAD vs BIM: What Your Construction Firm Needs to Know

Optimizing and digitizing design operations are important yet priority tasks for CIOs, CEOs, and decision-makers at every small construction firm. The completion of these tasks often involves a  debate about CAD (computer-aided design) vs. BIM (building information modeling) software. While both popular software offer computerized design tools, 59% of design and construction use CAD, and 36% use BIM. 

Despite being interconnected, the CAD and BIM software have significant differences that may make your small construction firm lean more toward one than the other. We will draw insights from Gartner’s Innovation Insight for Building Information Modeling [1] to present a straightforward breakdown of the similarities and differences between CAD and BIM software so you can choose which one is best for your business.

What are CAD and BIM?

CAD is the use of computers to digitally create design simulations of nearly everything, from buildings to integrated circuits to children’s toys. An effective CAD program is a digital assistant with preset tools to simplify and speed up the design process.

The acronym for computer-aided design, CAD, sometimes gets an extra ‘D,’ as in ‘CADD’ to imply ‘computer-aided design and drafting.’ Both CAD and CADD refer to interactive graphic design programs that automate elements of the design and drafting process.

BIM, an acronym for building information modeling, is a process that centers around creating and managing digital versions of buildings or infrastructure. A BIM system may consist of integrated or heterogeneous applications that make creating, sharing, and managing design content easier.

Small and midsize businesses (SMBs) in the construction industry can use CAD and BIM software to save time and effort in the design and review process. You can use CAD and BIM to generate 3D drawings based on 2D sketches, eliminating the need to create 3D digital models manually. This saves time and makes it easier to visualize how design elements interact with each other in your target space.

What are the benefits of CAD?

Saves time and boosts productivity

CAD offers various digital tools to speed up the designing, drawing, and rendering of ideas. It boosts designers’ productivity by slicing many hours off the creation process.

A CAD program can help you create instant copies of your design. If you want to apply a change, you can alter a design in any one copy, and the software will automatically modify all existing versions.

For instance, suppose you’re designing a series of 48 workspaces for an office building, and partway through the process, you realize you need an extra outlet in each space. Instead of manually sketching in an outlet 48 times, you can put it into the original design, and the software will automatically copy your addition to the other 47 versions.

Improves quality and presentation

CAD software enhances the accuracy and precision of your designs while making it easier to visualize and present your ideas and the final product. The program comes with tools for aligning and measuring objects, so there’s no need to worry about whether you’re getting accurate measurements. It can automatically snap objects into place, eliminating pesky gaps that could throw off your measurements.

Presenting ideas to clients and team members is easier with CAD because you can quickly render your project into a 2D or 3D model. You can also make real-time changes to a project while other stakeholders offer their input.

Reduces material waste

CAD helps you create detailed designs that fit your project’s demand, reducing material wastage. In addition, you can use the CAD program’s ‘integrated materials tracking’ feature to identify exactly how much material you need for each element of your plan.

For example, you may need to order light gauge steel to frame the interior walls of a warehouse. Instead of doing all calculations by measuring the ceiling height and the run of each wall, you can use CAD software to find exactly how much you need without any hassle. You can print a materials list and send it to your supplier.

What are the benefits of BIM?

BIM also has some design tools, but its primary benefits stem from its design data management tools. Here are some of the most significant advantages you get with BIM software.

Improves designers-stakeholders collaboration

With BIM software, you can instantly share plans, changes, and ideas with others involved or impacted by your design. This makes it a powerful collaboration tool, especially for complicated, multi-faceted projects involving many people simultaneously.

Suppose you are an architect designing the external water feature for an industrial park. While you’ve figured out where your supply line will come from, you’re unsure where to position the outlet pipes. There may be an underground electrical conduit in the way.

Now let’s say you and the electrician are using BIM software. You can sketch out a spot where you think the drain pipes could go and include a note to the electrician, as well as flag them so they know you have a pressing question. In moments, they can let you know where the conduit must go and how deep it has to sit according to local building codes.

Hence, the tool will make you feel confident about your design and help avoid conflicts.

Eases project visualization

One of BIM’s flagship features is its visualization capability. You can present 2D, 3D, and 3D-interactive design models that stakeholders and collaborators can check out digitally. For example, you’re designing a spiral staircase for a commercial building. A large, double-height glass window in front of it looks out on an adjacent lake. You’d like to take advantage of this view, but doing so may involve changing the angles at which people enter and exit the staircase.

With BIM, you can create a video demo of different angles from the perspective of someone ascending or descending the stairs. You can then quickly shoot these off to your client, explaining how each angle could impact guests’ views. You can consider the client’s input and improvise to incorporate it into your final decision.

In this way, a BIM system doubles as a client satisfaction tool and a productivity booster.

Reduces errors

As BIM software provides you with a life-like representation of your designs, it can also significantly reduce the number of errors made through the project’s lifecycle. Reduced errors lead to fewer reworks, which eases the job of everyone involved in the design-making process.

Referring to the above-mentioned water feature example once again. Suppose you couldn’t ask the electrician where the outlet pipes would go before designing. Instead, for time's sake, you put the drainage pipes just a few inches below the surface, reasoning that the electrical conduit could run beneath it.

While that may have been correct, it could expose your outlet pipes to freezing temperatures during the winter months, which could result in malfunctions or even burst lines.

BIM software will help you avoid this mistake and save time and money by preventing a frustrating redesign process.

Challenges with BIM and CAD

Disadvantages of CAD 

CAD is a comprehensive solution, but it comes with a big learning curve as it isn’t quite beginner-friendly. Most professionals have to invest hours in taking extensive courses that teach them how to navigate and leverage CAD’s features.

Moreover, CAD doesn’t consider some real-world issues that may impact your project. While BIM software can automatically flag design conflicts that may arise between an HVAC engineer and a structural engineer, CAD software may not automate such alerts.

Consistent usage of CAD may lead you to create similar designs as you repeatedly use the same presets and automated sizing tools. To avoid this, many people consider external opinions about their design ideas.

BIM disadvantages

While a BIM solution can be a great addition to your design portfolio, its use may highlight various challenges as it requires users to undergo training. The additional training time and effort may lower users' productivity in other work. BIM solutions may come with relatively steep price tags, deterring companies from investing in cost-effective solutions. 

Moreover, the system can complicate team collaboration because it involves many people simultaneously. 

For instance, suppose your team is using BIM and decides to get everyone’s approval before moving from one design phase to another. This includes the interior designer, structural engineer, contractor, and electrician. Let’s say the contractor loses internet reception for several hours, and the electrician goes on vacation. Without the consent of these stakeholders, you will have to put your project on hold, wasting the valuable time of many people.

In addition, with so many people offering ideas simultaneously, it can be difficult to decide which ones to approve or veto, as well as reconcile one with the other. It’s best to set up expectations and protocols for the BIM team’s collaboration process to avoid these issues.

CAD vs. BIM: Which software should you choose for your business?

Both CAD and BIM are popular choices for construction firms. Contractors, engineers, and architects often use CAD to design a range of electrical, structural, and mechanical elements.

BIM is a common go-to solution for engineers working on projects with several parts and components to incorporate into a larger assembly. While it’s often used to design and construct buildings, the engineering and architecture industries haven’t adopted BIM because of the complexities involved in onboarding.

Recommendations to prepare your small construction business for CAD and BIM implementation

To enable smooth, effective adoption of BIM and CAD software, you may find the following recommendations helpful:

• Get support from your company’s leadership before pitching a BIM or CAD tool. It’s easier to convince others when the leadership supports you.

• Use BIM or CAD as visualization tools to manage and monitor project and facility performance. When people see the benefits of CAD and BIM, they’re more likely to embrace each solution.

• Promote a data-focused culture in your company. This may involve rewarding data-driven decisions and services, which forces stakeholders to leverage some of CAD and BIM’s data-centric features.

• Set up standards and best practices around how people should use CAD and BIM, as well as how they should collaborate. Establishing standards beforehand can prevent miscommunications that may hamper your project’s flow.

• Use BIM and CAD to identify ways to generate more revenue and avoid overspending. For example, you can use them to design storage spaces you could rent out to others to create residual income.