Megalopolis is a large project that implements real-time procedural modelling of buildings from GIS data. GIS data and building descriptors are downloaded from a database and buildings are generated on the clients computer.
This allows multiple users to interact with an ever growing detailed 3d city without the need to download large models. Users can incrementally refine the city by interactively resizing and applying appropriate styles to buildings. The system can be seemlessly integrated with externally created cad models.
The following screenshots show a reconstruction of Dublin city, demonstrating how important landmark buildings such as the Trinity College Campus can be combined with procedurally generated buildings and roads. Implementation details can be found in my thesis.

Screen Shots

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Roof Modelling from Straight Skeleton

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Automatic Generation of LOD

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Texture Variations and Weathering

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Symmetry Hybrids


How we perceive the world is strongly governed by symmetry. Symmetry presents itself in both natural and man-made structures giving aesthetic appeal to the world. This paper presents an approach to form intuitive tree based representations that minimally describe input patterns. We explore how new hybrid patterns can be generated by grafting different symmetry trees together. A new algorithm is proposed to generate new hybrid patterns that maintain the overall appearance of the inputs while allowing control over the amount of variation generated.


Generating hybrids from symmetry has a number of useful
applications ranging from automatic content generation
for virtual worlds to artistic designs for wallpaper or ornaments.
We have tested this technique within a number of
domains. In each case inputs are given on the left.
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We segmented some flower patterns into a set of oriented labelled shapes. We obtained many interesting hybrid flowers with characteristics of the input patterns.

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We segmented the parts of ornamental designs and achievedmany new varying designs. The complexity of each pattern allowed hundreds of hybrid variations.

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Some interesting and unexpected results occurred with some of the hybrids. If symmetries are matched between different hierarchy levels of the input patterns’ symmetry
tree, we can obtain some fractal like effects. This occurs if we allow loops within the
symmetry tree. We have no way to adjust the depth of recursion within these fractal hybrids
without manually adding some control parameter to the resulting production set.

Building Generation

Input building facades (above) were segmented and hybridised. After hybrisation depth was added. Shaders and weathering effects where applied to the resulting 3d builing models to improve realism.

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