THE JERUSALEM CENTER   FOR PLANNING IN HISTORIC CITIES
Computerized Model One of the center's activities is building a Three-Dimensional     virtual model of the city of Jerusalem.     The center has received donations for building this model:   - From Silicon Graphics a workstation   - From Bentley Systems, Microstation/j software
The fundamental steps involved in creating virtual Jerusalem are as follows...
1.  The first step is obtaining maps from the municipality's GIS department.
These GIS maps provide topographic data including the various heights
Jerusalem is a hilly town), street names, names and outlines of buildings,
trees etc…All on separate layers. For Building the model,
the layers that are relevant to identify the information needed
and determine points of elevation and create a 3D topographic map
are activated.
The GIS information is created in AutoCAD with ArcInfo
and MapInfo and is provided in DXF format.
2.  As a second step-employing MicroStation/J-the building
outlines are brought to the height of the roofs and closed,
to create polygons. The "z" data is available in the
municipal GIS information.
3.  The polygons are then extruded,
adding volume and making them three-dimensional.
They are added to the topographical model.
From this point on, recreating the virtual city
becomes a solid modeling exercise.
Here the Center uses MicroStation TriForma software,
a platform for 3D building and plant applications,
including modeling and documentation.
The easy-to-use modeling tools allow quick sculpturing,
modifying and visualizing the city model.
4.  Now come roads, streets and traffic islands,
they are brought down in place to their correct
height on the topographical model.
This step also involves carving and pasting
such details as niches, tiled roofs,
external stepped balconies, fences, etc.
For this are used both MicroStation/J and Modeler.
5.  Then follow the apportionment of textures -
there are literally hundreds to choose from.
Textures such as brick, stone,
stucco or rough plasters are assigned to exterior walls.
Different colors to different elements make up
the picture on the screen.
6.  Finally, specific buildings are "taken apart" Details
such as facades, doors, windows, etc. complete the design.
Required for these processes are digital photos -
taken both from the air and in situ -
which are then pasted as a raster screen onto the
computerized buildings.
So far, the Center's computer team has concluded
work on 20 maps of the center of town - an area of 2x2.5km.
Prominent edifices such as historical structures,
public buildings, churches and synagogues and high rises
get special treatment. While ordinary buildings remain as cubes,
others, somewhat more important, get 2D facades,
while the above-mentioned prominent structures
receive a 3D fa?ade plus texture and colors.
In dealing with a city model the hardware
has to be "strong" enough to handle large files
and process them as fast as needed.
SiliconGraphics is the right choice.
1.	Simulation for architectural and urban planning needs. Checking panoramas and skylines. Checking structures from pedestrian and vehicle passenger points of view.
2.	Environmental testing. Microclimate effects: Sunlight and shadow. Noise effects. Ground slopes.
3.	Showing engineering infrastructures in 3D. Showing statutory state in 3D.
4.	Profiling by: Dates and eras, styles and architects.
5.	Presenting parts of the model on the Internet.
6.	Information.
This model has been created with data from the municipal G.I.S. department and the city's computerized maps.