The first version of AutoCAD Civil 3D was released over a decade ago, so I am always surprised when I see customer feedback that includes, “Bring back Land Desktop”. To me that is like saying, “Bring back the word processor”.
I get it. Land Desktop was a good solution for its time. Unfortunately, the problems that civil engineers and surveyors are being asked to solve got bigger than it could handle. More and more engineering firms and government agencies are realizing that old ways are no longer good enough. According to various customers we’ve interviewed in the past couple years, the move from more drafting-centric processes, supported by something like Land Desktop, to model-based design is necessary if you want to survive and thrive in the world of civil engineering.
Consider a company LandmarkJCM, a civil engineering consulting firm in the Northeast. We had the opportunity to visit the team in their office where they talked about what motivated their move to model-based workflows. Their decision was instigated by the need to be nimble and efficient without increasing client cost, as pressure to reduce fees was rising as competition got stiffer. Like most engineering firms, they were looking for ways to maintain or increase the quality of the product they produced, yet do it more efficiently and at a lower cost
As civil engineering companies begin to reap the benefits of adopting BIM workflows, the fear of becoming extinct is motivating others to consider jumping on the bandwagon. It is understandable that you might be a bit anxious about needing to change not only the software you’ve grown to know and love, but also the workflows you’ve become proficient at. Common questions we are often asked are:
- How do model-based design and the way work was completed in LandDesktop compare in terms of time?
- How will my workflows change?
The Element of Time
Model-based design appears to address challenges design teams have dealt with for years by allowing designers and contractors to engage directly with site information and a virtual representation—the computer model—of the actual project.
Feedback from customers suggests that design time is modestly increased with the move to model-based design as firms and agencies make the transition. The initial increase, however, is not uniformly distributed over the design timeline. Rather, our users have told us that the design effort is moved forward in workflows. That is, a relatively large amount of time is spent in early design stages. This is due in large part to the fact that creating a 3D model is more complex than creating 2D depictions. This is a good thing, as the engineers’ skills will have a much greater impact in earlier, conceptual stages of a roadway project, compared to later stages which tend to be more ‘cookbook’ in nature. Working in greater detail in early design stages measurably improves project quality; for example, some features that have been typically ‘under-designed’, such as curb returns at intersections and access points are worked out precisely, contributing to a higher quality finished project.
Once work on the model is completed, it’s used constantly in ways that reduce time and effort downstream; volume calculations, plan creation, and other traditionally tedious design tasks are largely automated by referencing early design work. Moreover, designers feel that the modest increase in upfront design time is more than offset by the gains in automated documentation updates and error checking that are realized when late stage design changes are made.
Even on early model-based projects, civil engineering teams find that expected gains in plan creation and error checking are, in fact, realized. This improvement in error checking has been confirmed by actual construction experience, as contractors report fewer errors in plans and reduced construction slowdowns (see related post on Real BIM for Infrastructure ROI).
As might be expected, as more people are trained and experience is gained, design time increases experienced during the transition are largely erased. In the end, you not only get a high quality product, but it is completed in less time than it took using drafting-centric approaches.
Process Changes Vary
Some changes to workflows are needed to create construction-ready models, but many aspects of the design workflow remain relatively unchanged. For instance, creation of digital terrain models and the identification and refinement of centerline alignments are all very similar.
While some things remain unchanged, there are definitely some differences. A good example is cross sections. For a rural highway plan created with traditional workflows, designers have typically created cross sections every 100 feet. Since design intent was conveyed by plans, each cross section needed to be included in the plan set, whether or not there were substantial changes from adjacent sections. With a model-based approach, your focus may shift to the creation of a construction-ready model. Designers still have to spend time defining cross section templates at transitions, but surfaces can be ‘extruded’ from section to section. Only relevant cross section sheets need to be created, and much of this work is automated by newer software like AutoCAD Civil 3D. The best part is, if cross section templates are modified at any point during design, the plan sheets are automatically revised. Try that with something like LandDesktop.
Designers find that these types of gains free time to do more detailed work at intersections and access points. Special attention to the building of accurate intersection and access point models are needed to create a construction-ready deliverable. Getting it right reduces mutual frustrations due to inadequate information and poor communication of the intricate details of these areas.
Focus on the Model not the Paper
If we continue to consider the cross section example, to fully optimize model-based design and automated construction techniques, workflows must be adapted to focus on accurate surface models versus individual cross sections. Rather than checking cross section sheets, for example, review methods may be developed that verify the performance and constructability of the surfaces, with an eye to their use by contractors preparing bids and integrating the surfaces into automated work. Collaboration with contractors and consultants is facilitated by use of visualizations produced from the model; they may also be useful when presenting projects to the public. You can still produce the necessary construction documentation if needed, you just won’t need to put as much effort into their creation.
Eye on the Future
Even though LandDesktop might not have been ‘broke’, civil engineering processes continue to benefit from the ‘fix’ that advancement in technology and new software enables. With the ever changing way that people and devices are connected (think the internet of things), ideas and feedback are gathered (think crowdsourcing) and projects are built (think drones), there’s no going back.