There are a growing number of 3D tools that link to project planning applications to help streamline the construction process. AEC Magazine asked three proponents of these new generation tools for their views on the technology.
With reference to the growing number of packages that link architectural/structural CAD systems to project planning applications, is it essential to use 3D models and if so, what are the obstacles (technical and cultural) to realising the benefits of integration?
Phil Bernstein & Amar Hanspal, Autodesk
As individual building projects increasingly involve partners, clients and suppliers from around the world, 3D models are becoming the lingua franca of design – and round-the-clock execution is not only advantageous but increasingly necessary to on-time, on-budget design and construction.
At issue are benefits than reach well beyond integrating applications. Architects, engineers and builders are faced with more than a question of linking CAD and planning applications, or using 3D models. The industry must decide whether to embrace BIM principles and project collaboration technology that could transform their business – rather than simply settling for application integration.
Architects and engineers create vital information that must flow throughout the building process. A sub-contractor may request digital design information derived from construction documents to increase accuracy in fabrication. And design and construction tasks are merging in new delivery techniques such as project alliance, design/build, and other initiatives.
“Integration,” however, is open to broad interpretation, and does not inherently present the sum total function of a building design’s parts. Nor does integration of project elements accomplish team integration – that is, collaboration.
Certainly, use of 3D models can help. Modelling in 3D conveys complex design concepts in an intuitive fashion. Building information management (BIM) tools take 3D a step further, simulating architecture and systems infrastructure to present computable data. While 3D modelling is not mandatory for every single aspect of design and construction, it’s clear where there are advantages to having graphical elements represent real values calculated from real measurements, physical interferences between simulated system elements, and so forth.
This sophisticated modelling is also a pre-requisite to the use of design data by project planning and collaboration software. Indeed, using computable building information to connect well-defined business process, rather than the distinction between 2D or 3D, is the technological hurdle that must be overcome for integration and thus effective, meaningful communication.
The cultural obstacles to such collaboration include legacy technology, investments in conventional design techniques, and the tendency to use new tools in old ways. In fact, the advent of 3D modelling demands greater collaboration, as individuals are empowered to work simultaneously on project elements. Faster projects delivered with increasingly integrated supply chains will demand this.
If the building industry is to overcome the cultural barriers to integration, technology must support business process integration. Most scheduling and planning applications fall short of achieving the accountability that results in collaboration. Reliable technology that alerts team members to design changes – and to the actions they must take to keep workflow moving – helps shepherd myriad tasks and details toward the desired end: a project finished on schedule, on budget.
The industry only need turn to the Freedom Tower project to see what’s possible, beyond superficial forms of integration. To facilitate communication across a team of hundreds and soon thousands of people, lead architecture firm Skidmore, Owings & Merrill LLP is implementing BIM principles and a Web-based project management service, so that design, engineering and production teams work from the same data, understand design constructability and manage workflow and accountability.
Phillip G. Bernstein, FAIA, LEED AP, is vice president, Autodesk Building Solutions Division. Amar Hanspal is vice president, Autodesk Collaboration Services Division.
Dominic Gallello,CEO, Graphisoft
Instead of linking CAD packages to scheduling systems, the future is to drive the schedule planning and the production control process from the estimating system. The model feeds the estimating system and the estimating data feeds the schedule. Up to now, linking the schedule to a CAD package was the natural first step that many construction companies and vendors have taken. Why? Because it is relatively easy. Although the 4D simulations make very sexy marketing presentations, they are not being used for their intended purpose – to drive production planning & control.
Instead of linking CAD packages to scheduling systems, the future is to drive the schedule planning and the production control process from the estimating system
The world is going to change dramatically in construction planning. A new breed of ‘location-based’ scheduling systems are coming onto the market which are significantly more appropriate for construction-oriented scheduling. They will require Bill of Quantity information which can most easily come from the model.
Activity-based (designed for manufacturing) versus location-based (designed for construction)
There are two main methodologies for scheduling work.
- The dominate methodology is ‘activity-based’ scheduling. It has manifested itself in techniques such as CPM, PERT, Generalized Activity Networks and Critical Chain Method. The development of activity-based scheduling was largely supported by the US military and NASA for manufacturing weapon systems. The characteristics of this kind of activity includes a single location, complex, pre-assembled components, highly sequential process, just-in-time delivery and one of many critical paths may be identified. Unfortunately, this does not describe a typical construction process at all.
- The second methodology is ‘location-based’ Scheduling. Location-based scheduling is perfectly suited to the needs of construction. It deals very effectively with multiple locations; the need to schedule the precise location of a work crew(s) in order to minimized site management problems; the need for schedules to indicate, manage and protect workflow; the need to change the sequence of an operation without disturbing precedence logic; and the need to take into account site constraints (material storage & location conflicts). The best technique to represent the flow of crews from location to location is Line-of -Balance.
Location-based scheduling, when combined with a Bill of Quantities per location, addresses the two biggest challenges facing schedule planners today: a) accurately forecasting durations for tasks and b) measuring actual productivity versus the plan and forecasting the impact during the construction process.
So going forward, the integration of modelling, estimating and scheduling will be as follows:
- Model – provides quantities and locations
- Estimate – turns the rough model quantities into actual quantities of resources (real world materials)
- Schedule – the schedule combines the quantities with crew productivity rates to determine a highly accurate schedule and support timely production control.
In order for construction companies to achieve this, the two issues that have to be resolved are:
Technical – The key word here is ‘integrated’. Up to now, some leading edge users had to use home grown developments to try to integrate data together on their own. An integrated suite of applications by the vendor community that provides seamless data flow will be essential.
Cultural – Driving process change across the various departments in a construction company is a major barrier. As usual, it will take commitment from the top to make this happen.
The benefits of this new location-based workflow to drive schedules will include projects that are delivered more predictably with less cost. By minimizing interferences between crews and eliminated days of waiting time, the nature of construction projects will change substantially.
Philip O’Brien, Marketing Manager, NavisWorks
NavisWorks, a leading developer of interactive viewing technology and 3D CAD review solutions, believes that the productivity and quality benefits that can be enjoyed by embracing the use of 3D information rich digital design are considerable. We are committed to enable the full exploitation of the benefits of 3D digital designs in the building, construction and facilities markets independent of the authoring design software. We recognize that the widespread adoption of 3D modelling may be some time away and perhaps the best authoring tool is yet to appear. Despite this we are confident that it is the powerful business possibilities offered by modelling objects that know what they are, where they should be in relation to other objects and can be interactively linked, either directly or through external databases, to applications for 4D, 5D and nD use that will force change. The return on a 3D investment and the process change that it accelerates is a more effective business with a common project view that enhances collaboration, design integrity and reduces waste to boost profit.
Linking time to a 3D model may seem two dimensions away from reality to a 2D CAD user but links with project planning is just one benefit of embracing 3D intelligent models are an exciting advance on computer aided drafting and 2D object-based modelling. Project planning is a role with growing influence within the project team and bridging the human understanding gap by using technology to link design CAD output to project software enables better communication leading to fewer errors in project control, easy ‘can-it-be-built’ checks, clarity for the client, efficient site planning and a visual environment for tracking actual versus planned.
NavisWorks is uniquely positioned to maximize the benefits that result from putting a 3D design model at the heart of the process of design, construction and facility management. Roamer, the dynamic core of the NavisWorks design review solution, reads and combines the most popular 3D native design formats for interactive visualization and review. For NavisWorks the 3D model is essential but it need not be built in any “special” way to link to project planning applications and we do have customers who are benefiting from this feature by simply adding a nominal height to 2D lines. Plug-in components for Roamer provide the ability to add photorealism, check for interferences, publish freely viewable files and 4D schedule simulation.
NavisWorks Roamer plus the TimeLiner plug-in adds 4D schedule simulation to NavisWorks by linking to project planning applications. TimeLiner imports schedules from a variety of sources [Primavera, MS Project & Asta Powerproject] to allow the connection of objects in the model with tasks in the schedule; simulate the schedule showing the effects on the model, including planned against actual schedules and export images and animations based on the results of the simulation. TimeLiner will automatically update the simulation if the model or schedule changes.
The ability to link 3D design output to project planning software extends the value of both. All key project stakeholders share a clear understanding of design intent, construction plan and current status. The design, planning and construction teams can unite with a common focus upon a single project model that is relevant to everyone’s responsibilities and of use to all to complete the job on time, on budget.
Extending the use of the 3D resource will improve communication between designers and planners and sponsor process improvement including the adoption of industry/project/corporate standards for 3D model creation so that downstream use is easier.