Welcome to Cape Town

I went to Cape Town last week to do some CityEngine demonstrations. So I decided that the best way to show the abilities of CityEngine is to create a quick WebScene of Table Mountain and its surroundings...

I started by importing (dragging and dropping really) a TIFF image for the Cape Town CBD area into the scene. I used a standard JPEG aerial image as the Layer texture.

  
To start with, I had some building footprint data, but not a lot. Luckily I had the entire set op parcel properties for the area. I decided to use the real building footprints where possible and fill in the rest by creating procedural buildings from the properties layer.

The building footprints did not have a height attribute, instead it had a Floor Level (FLR_LVL) attribute. I proceeded to create a procedural rule which assigns a Height attribute based on the Floor Level attribute. If a feature had 0 as a value for floor level, the rule assigns a random value between 2.1 meters and 2.4 meters to Height. If the feature has a valid floor level value, the floor level is multiplied by a random value between 2.1 and 2,4 meters and assigned to Height.

Finally the rule extrudes the feature according to Height and colors the building light grey.

The next phase was to flood the existing open spaces with  procedural buildings.
The first step of this phase was to create an offset distance for the each building from the street. The offset was set to between 5% and 25% of the property's longest side.

Two additional attributes are defined, namely Minimum_Height (5) and Maximum_Height (50). The maximum height had to be reduced from 130 meters to 50 meters after my love of skyscrapers created a city skyline resembling a pincushion... 

The property features are then divided equally and assigned a shape and finally extruded to a random value between the minimum and maximum heights.
25 % of the features generated a U - Shaped building;
25% generated O-Shaped buildings
25% generated L-Shaped buildings
and the remaining 25% kept the original feature's

shape.

 The second to last step was to add the additional city-features such as Parks, Rivers, Railway and the Ocean. The water features were given the '__water' suffix to create realistic water textures when exported to a web scene.

The final part of the scene was to add a Sketch Up model of Cape Town stadium.

The outcome was a simple representation of the city without spending too much time on building generation. By coloring the buildings grey (instead of detailed textures), the differences between built-up areas and vegetation in the city becomes clear.