Mapping Image Data to Rule Attributes

Map layers are a very powerful tool to control CGA shape grammar rules. Any attribute that you have defined in your CGA shape grammar rules can be mapped from an attribute layer. This allows you to guide your rules by maps. Typically, maps are used for controlling building attributes such as height or appearance, level of detail, or land-use mixes.

The image below is going to be used as source image to control the height of a set of buildings.


Image to be used as skyline map

 

Assume you are starting from a scene with a set of building footprints like in the image below:


A set of building footprints

All shapes have a rule file assigned that extrudes the footprints to a certain height
attr height = 30
Lot --> extrude(height)

Creating the map layer

Create a new mapping layer, choose your skyline map, set the bounds to fit your scene, and add a new attribute skylineValue. Its range will define the range of the building heights.


Settings for skyline layer


Skyline layer added to the scene

Connection Editor

Select all footprint shapes, and click on the connection icon for rule attribute height in the Inspector. Choose layer attribute, select the new Skyline map layer and the attribute skylineValue


Connecting rule attribute height to Skyline Map Layer


Building heights controlled from Map Layer

 

 

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