Three-dimensional modeling for civil engineering projects is an evolving technology. This is evident in part by the lack of agreement on exactly what to call it. Autodesk, Inc., refers to it as building information modeling (BIM), using the term “building” in its broadest sense — as an active process, not just a structure. Bentley Systems, Inc., on the other hand, distinguishes between 3D modeling; BIM; and intelligent, information-rich 3D modeling used for civil engineering projects.
“3D modeling and BIM are not synonymous,” said Ron Gant, director of global marketing, civil engineering for Bentley. “BIM can exist and often does in a 2D model. 3D modeling does not imply that there is intelligence or information associated with the modeling process.”
Gant said that Bentley’s civil engineering software has had 3D modeling capabilities for more than 25 years, but the company began adding intelligence to the models only 10 years ago. And as the intelligent model has evolved with each software release, engineers now do “3D Civil Information Modeling and not just 3D modeling,” Gant asserted.
Autodesk’s Adam Strafaci, senior industry marketing manager, Infrastructure, AEC Solutions Division, agrees that the information behind the model is key. “When we talk to civil engineers about the value of BIM, the conversation usually comes around to the power of the information inherent in the 3D model,” he said. “In other words, it’s not enough to just have a 3D model. It’s the information that makes it really valuable.”
Leaving aside the name debate, how are civil engineers currently using intelligent 3D modeling/BIM?
“While most sectors of civil engineering are taking advantage of BIM and 3D modeling to some degree, we see the most traction in transportation; facilities like wastewater treatment, electric substations, and hydropower plants; and land development,” Strafaci said.
But the drivers for adoption vary by sector. For transportation projects, the greatest driver is the increase in project complexity and the demands for delivering projects with greater transparency and predictability, Strafaci said. In facility design, the driving force is the demand for multi-discipline coordination between civil engineering, structural engineering, architectural, process mechanical, electrical, instrumentation, and HVAC disciplines.
“With land development there is an obvious adjacency to the architect using BIM to design the buildings,” Strafaci said. “So often the civil engineer is being asked to participate in the BIM process. The compelling benefit is managing the constant change and iterations that come with optimizing a piece of land to meet multiple objectives.”
Bentley’s Gant agrees that within civil engineering, the transportation sector has taken the lead in adopting intelligent 3D modeling. He cited time and costs savings achieved with machine-guided construction as a driver for contractors to demand digital models for construction.
Dave Carlson, vice president of development, Carlson Software, said that in addition to the use of 3D models for construction machine control, surveyors are using the design model in data collection software, such as Carlson SurvCE, to check elevations in real time and compare the as-builts against the original design.
“This is not simply the ‘finished ground’ surface, but a data-rich model that takes into account any subgrades, trenching, and other subsurface design elements and their parameters,” Carlson said. “In addition, … Carlson is working closely with Esri to build strong bridges between the CAD and GIS environments to enable surveyors and civil engineers to complete the circle of planning, design, construction, operation, and management of projects.”
Asset management is another evolving sector for 3D modeling as the value of intelligent, information-rich modeling is recognized as an asset for operations and management, Gant said. “The information created in the design phase, if moved forward through the life cycle, removes one of the greatest inefficiencies between engineering and operations and we truly have full life cycle information management.”
Another application of 3D modeling, especially in earthworks, grading, and finishing operations, is to value engineer designs, according to Alan Sharp, segment manager – Site Positioning Systems, Heavy & Highway Construction Division, and Chris Richardson, marketing manager, Trimble Planning Solutions. “The models help minimize earthworks, shorten haul routes, and plan 3D construction routes with cost of construction in mind,” Sharp and Richardson said. “3D models are also created in the bid process as contractors strive to create more accurate quantity estimates and sharpen their pencils further in an increasingly competitive world.”
New features and capabilities
As civil engineers and surveyors adopt intelligent 3D modeling for an increasing range of projects, software developers continue to expand their programs’ capabilities and functionalities.
Autodesk highlighted three new capabilities of its latest versions. First, a new point cloud feature in AutoCAD Map 3D 2011 and AutoCAD Civil 3D 2011 helps incorporate point cloud data from LiDAR scanning into workflows. Second, Autodesk Civil Visualization Extension for AutoCAD Civil 3D and Autodesk 3ds Max Design software provides a link between the design model created in Civil 3D and renderings in 3ds Max Design. Third, Autodesk Storm and Sanitary Analysis Extension available for AutoCAD Map 3D and AutoCAD Civil 3D provides a comprehensive hydrology and hydraulics analysis application for helping to plan and design storm and sanitary sewers.
According to Bentley, “3D Civil Information Modeling” — using products such as its Power InRoads, Power GEOPAK and MXROAD — has evolved into a dynamic and interactive process, allowing engineers to make changes on the fly and see the effects of those changes as they are made. Bentley also added interactive and batch processing of models for interference and clash detection.
Bentley civil applications produce an iModel (information model) that can be viewed and reviewed in tools such as ProjectWise Navigator where users can combine disparate models from other Bentley applications or from other vendors. These combined models are viewed in 3D where clash detection or management and construction review are simple and straight forward, Gant said. Additionally, scheduling information can be combined with the model to allow users to visualize time-lapse construction or to simulate construction.
Carlson’s newly released version 2.5.1 data collection software, SurvCE, features new interoperability with Esri ArcGIS 10, making it possible to read the model database to set up field codes, collect data with GIS attributes to that schema, then write Esri-compatible, centimeter-accurate .DWG files directly from SurvCE.
Carlson 2011 office products, including Carlson Survey and Carlson Civil, will work with Esri ArcGIS 10 in a .DWG file format with Esri format features and attribute data, Carlson said, which makes this .DWG file a type of geodatabase that will enable sharing a model from planning with Esri software, to design with Carlson software, back to operations and maintenance with GIS.
Trimble Quantm Desktop helps users realize lower alignment construction costs, minimize environmental and community impact, and reduce project planning time, according to Sharp and Richardson. The program selects and generates 3D corridors and alignments, creates millions of alternative alignments, and returns a range of best options.
3D road ahead
Steve Biver, civil product line manager, Eagle Point Software, expects 3D modeling to become increasingly important for civil engineers in all sectors for two reasons. “First, 3D modeling allows for quick visualization of the project during the early design phase. This enables project stakeholders to better understand the proposed alternatives and select the appropriate design. Second, BIM will enable engineers to spot potential conflicts in their designs before they get built. When the information models contain more than just the terrain, clashes between roads, bridges, and utilities will become readily apparent and can be resolved during design.
“We see tools that get the model built quickly as a vital part to greater adoption of BIM,” Biver said. “The sooner an engineer or designer can get to a point where they can iterate their design is key. This allows the engineer to analyze alternatives and scrutinize project performance, which ultimately leads to the most cost-effective design.”
Lower cost is the theme cited by Trimble’s Sharp and Richardson. Modeling capabilities allow planners and engineers to redesign routes based on value engineering principles and changing construction techniques, they said. It provides routes based on lower cost, minimized environmental impacts, or optimized equipment operations.
Additionally, advances in GPS, wireless communications, and data collection software that enable land surveyors to collect and stakeout the data for 3D modeling will increase their involvement with the BIM process for road, water, and land development, predicted Carlson. “The construction permitting process within various jurisdictions is also expanding to include the submission of models, in addition to traditional documentation,” he said.
During the next five years, Autodesk’s Strafaci expects engineers to take BIM and 3D modeling beyond the realm of design and construction into project planning and asset management — covering the full infrastructure lifecycle. “An end-to-end BIM process will allow engineers to take a more holistic approach to projects and use the information inherent in the 3D model to solve larger challenges like the long term ROI of a project or overall sustainability,” he said. “More forward-looking engineering firms are starting to do this now. But we expect that in five years, this practice will be standard across many sectors of infrastructure including transportation, water, and energy. In addition, we see the use of BIM extending into larger scale efforts including modeling of entire cities.”
Gant expects a similar evolution but said that BIM, conceived in a vertical engineering and construction environment, must evolve into “Civil Information Modeling” to serve the horizontal world of transportation. “Transportation challenges of scale, ellipsoid, and engineering unit (U.S. Survey Foot) must be addressed,” he said. “As they are being addressed in Civil Information Modeling, transportation will reap the benefits of information and data created once and shared by many from design to construction to operations to maintenance.
“We continue to evolve from line strings and membranes to 3D solids where pavement sections are not just a group of lines meshed together to simulate a 3D shape or where a drainage pipe is actually a 3D solid pipe,” Gant said. “It’s starting to sound a lot like smart objects and object modeling isn’t it? Civil engineering design is evolving quickly!”