Current Work | Existing Models | Resources
We are interested in a number of aspects of Urban Environment models :
- Large-Scale Rendering including
- level of detail
- image-based rendering
- visibility computation
- Model Maintenance
- Procedural generation of models
- Integration of models from different sources
- Run-time distribution
We are currently building new city models for use on the City project within the Equator IRC. For the purposes of Equator we
are specifically interested in model maintenance and on-line access
from mobile sources.
Since the original models were built, much better GIS data has been
provided, so building outlines, heights, pavements etc... will be much
more accurately modelled.
The original London Demonstrator models (see below) are still used for worked on dense crowd
simulation and visibility research.
For the COVEN Project we built a single integrated
system that had a 17x10km generated 3D model with inserts modelled at
higher resolutions. This was known as the London
Demonstrator. It was novel for a number of reasons:
- Its being built on a generic VR platform (DIVE) meant that it was easy to support
collaboration and interaction.
- The scalability extensions were scriptable in Tcl, so it was
possible to integrate several simple visibility techniques and
have higher-level scripts reason about when to use each
- Support for a semi-hard frame rate limit. Utilising some
crude but effective adaptive clipping techniques.
- Extensive use of aura/focus/nimbus and spatial partitioning
to dictate awareness between users.
- Within the application we integrated a build mode
that allowed us to run the application from online resources
(e.g. VRML models), optimise the graphics (material,
triangle-stripification, linearization), and save as binary
compressed internal format. The resulting models could be loaded
much faster across across a network (total resources came to
- Dynamic, context-sensitive user interface. This is still
unusual in VR toolkits.
The following pictures show the extent of the model. These parts were
built by an automatic process from the GeoInformation Cities Revealed
data set for London.
Certain parts of the model were modelled in greater detail. The UCL
Pearson building was modelled in AutoCad, other parts in Canoma. How
to integrate models from such disparate sources and have them relit to
look consistent is an unresolved problem.
When built (1999), the application was targetted at SGI Indigo or
Onyx-class performance. The following snapshots show the application in action and demonstrate the frame-rate limiting.
Of course now, this class of performance is achieved on consumer
hardware. The following pictures are taken from a 800MHz Pentium
machine with a GeForce2 card. The 2nd shows the detailed local model.
Note though that it is still easy to hit the polygon or pixel fill
limit, and it will be a few years before machines can render the whole
model. Well before that happens, we will build bigger models.
The London Demonstrator served as a test-bed for crowd
modelling and interaction experiments as the following snapshots
show. You can also see a snapshot of the Pearson building model.
The DIVE London Demonstrator application itself is not under
development at this time. Since it is such a complex application, we
use it to stress test revisions and ports of DIVE itself.
- Can I have the whole London model?
- Sorry, but because the base 2D data is licensed, we can
not give away the 3D data set. This may change for modern
versions of the. You are welcome to download the UCL area
part of the model.
- Where can I get the UCL Area model?
- This can be
browsed as VRML or as an interactive demonstration within DIVE
- A.Steed and E.Frecon, "Building and Supporting a Large-Scale Collaborative Virtual Environment", Proceedings of 6th UKVRSIG, University of Salford, 13th - 15th September 1999, p59-69. This paper won the best paper prize.
- A.Steed, E.Frecon, D. Pemberton and G. Smith, "The London Travel
Demonstrator", Proceedings of the ACM Symposium on Virtual Reality
Software and Technology, December 20-22nd 1999, pp. 50-57, ACM Press, ISBN
- Urban Models at UCL
Queries about the models and applications: Anthony Steed, A.Steed@cs.ucl.ac.uk