The benefits of 3D modelling on large projects are numerous, especially from using analysis and simulation. Arup’s development arm Oasys has an exciting new application for simulating individual pedestrians up to massive crowds. Martyn Day takes a look.
In the 1800s only two percent of people lived in cities and towns. By 1950, this had increased to 30 percent. Today more than half the world’s population, 3.3 billion, live in a city. Statisticians estimate that by 2030, 60 percent of all people will live in a metropolis. Here’s some more statistics. Up to 180,000 people move to a city each day from rural areas in search of jobs, opportunities to improve their lives and create a better future for their children. This is the first time in human history that the majority of the world’s population is living in urban areas.
With increasing city populations, density can quickly outpace existing infrastructure and so we are seeing heavy investment in public spaces, trains, airports and roads. Whether it be Shanghai’s transport system or new facilities for the London Olympics, designers are having to consider creating or modifying spaces and systems to cope with the flow of hundreds of thousands of people, while keeping a mind on overcrowding, fire safety, evacuation and in extreme cases, the threat of terrorism. While CAD can assist in documenting the geometry, flow and space usage must be simulated.
Oasys
Oasys is the software development arm of Arup both providing tools to its parent company, as well as the industry at large. Its biggest products to date are Mail Manager and Columbus, which are low cost document management utilities, however it also has a wealth of powerful analysis tools for geotechnical, structural, seismic, sustainability and simulation. Mass Motion is a product that came out of the company’s use of existing commercial crowd simulation solutions that failed to meet their in-house designers’ needs.
MassMotion
Based on Autodesk’s 3D animation tool Softimage, Oasys has built a radical new external crowd simulation and analysis engine, which can literally display and calculate truly massive numbers of individual agents which negotiate an environment in real time. All calculations are based in real time, in 3D spaces, with ‘way-finding’ as individuals negotiate large and complex multi-level environments.
The model can contain built-in discrete events, such as escalators, lifts and turnstiles, which impact flow. It has been tested using 350,000 agents and it is believed that the design is scalable beyond that.
As the system runs inside of Softimage, it is possible to use the environment to create the building geometry for the simulation. Alternatively, geometry can be imported from popular CAD systems such as AutoCAD, MicroStation, Rhino, 3ds Max and even SketchUp. In simulations, unnecessary detail should be trimmed away, so perhaps it is not too mad an idea to produce some rough geometry in Google’s free SketchUp. File formats supported include .3DS, .fbx and .obj.
MassMotion is a 64-bit Windows multi-threaded application which takes full advantage of multi-core processors and any available RAM. It will run on a fairly standard PC or laptop and the more grunt your machine has the better the performance. The first time I saw MassMotion was last year on a laptop and it was very impressive even then. I can only imagine the massive benefits of a decent multi-core CAD workstation.
Before the simulation, the geometry needs to be classified. These can be floors, links (like escalators or lifts), barriers and portals. Then ‘spawn’ points or ‘portals’ need to be assigned, which are places where the agents originate, together with destination zones for the agents to head toward. Once the size of the crowd is decided, on running a simulation, agents will be produced at these origin areas and then negotiate the buildings and control systems to achieve their individual goals. On reaching their destination they vanish.
According to Oasys, Mass Motion is the only software that allows the programming of individual personalities with unique agendas from start to finish in their journey through the environment. The software automatically validates the data and tells you if you have missed anything.
Huge crowds are automatically computed in real time and it’s easy to stop the simulation for re-design or re-test without the burden of lengthy remodelling or reprocessing cycles. As you would suspect, all the simulation is based on academic research, supported by actual observed crowd behaviour. Agents react to events in real-time, so should an escalator become overcrowded, they will seek an alternative route, the same if a gate should change from open to closed.
The real-time agent graphics are perhaps a tad ‘blocky’ but this is absolutely fine for the purpose.
The videos that Oasys has created for the marketing of the product include some very slick 3ds Max style rendering of people walking about but these have been created post-analysis and are an additional benefit which needs additional post-simulation work. The real-time view is much more basic.
Analysis
The software can provide feedback on how long ‘A to B’ journeys took, flow rates for doors, stairs and escalators, together with queue sizes, wait times and the comfort rating in different parts of the model and at different times. Bottlenecks are highlighted with colour density maps to quickly identify hotspots. This data can be output as graphs and other visuals.
Applications
Oasys is aiming Mass Motion at firms that need to simulate transit operations, venues/special events, airports, terminal planning, district planning and evacuation scenarios for; stations, airport terminals, healthcare facilities, office towers and arenas/stadiums.
Conclusion
MassMotion is an incredibly impressive product. Looking at live simulations of train stations which have trains coming and going, with respective platform build-up between trains, you actually know what that would feel like. Also a simulation of the crowds at the annual Hadj pilgrimage in Mecca, where tens of thousands of people circle around the Kaaba, the simulated motion looks so close to the actual footage. This is a highly accurate product.
The bad news is the price. First you need a copy of Autodesk Softimage, on top of which is £20,000 for a perpetual licence. This isn’t the kind of technology that every practice can afford but on multi-million pound projects I can see this becoming perceived as a very valuable tool from the conceptual stage onwards. According to Oasys the product is competitively priced compared with the competition (www.massivesoftware.com) or the applications that have come from the games industry.
There is a hefty 40 percent discount running at the moment as an introductory offer. If you are working on large projects, you need to get a demonstration.
