Procedural City ModelingImplemented As A Blender Plug-In

Kevin Mullane

Supervisors:Kevin GlassShaun BangayHannah Slay

Project Aims

• Procedural Techniques for the Creation of Virtual Cities

• City Road Layout Templates

• Preliminary Building Generation

Overview

• Project Background• City Generation Process• Implementation Techniques• Road Layout Template Implementation• Generated City Results• Conclusions

Project Background

• Text-To-Scene System– Current project of the Virtual Reality Special

Interest Group at Rhodes University– Aims to generate interactive 3D environments

based on textual descriptions.

• Blender Python API– Open Source 3D Modelling Package– Implements a Python Interface– Allows for Procedural Scene Generation

City Generation Process

• City Limits Delimitation– User Parameter– Defined By Landscape– Randomly Generated

• Highway Network Generation– Raster / Checkered Layout– Branching Layout– Radial Layout

• Suburb Region Extraction– Region Extraction Algorithm– Structure Heights

City Generation Process

• Road Network Generation– Region Subdivision– Regular Quads and Triangles– Roads and Intersections Extracted

• Block Region Extraction– Region Extraction Algorithm– Blocks Resized

• Building Extrusion– Quads Extruded Upwards– Height Within a Determined Range

City Generation Process

Implementation Techniques

• Road Segment Generation

• Region Extraction Algorithm

• Regulated Subdivision

Implementation TechniquesRoad Segment Generation

Ray Generation

Endpoint Generation

Legality Testing

Road Layout Evaluation

Best point is chosen

New Road Segment is created

Road intersection testing

Endpoint proximity testing

Implementation TechniquesRegion Extraction Algorithm

Initial Road Selection

Smallest Angle Selection

Record Road Traversal and Direction

Accumulate Interior Angles

Exterior Region Detection

Implementation TechniquesRegulated Subdivision

Adjacent Edge Triangulation

Adjacent Triangle Evaluation

Shared Edge Removal

Quadrangle Subdivision

Triangle Subdivision

Further Quadrangle Creation

Road Layout Templates

• Raster / Checkered Layout– Restrict Road Generation Angle– Restrict Road Segment Lengths

• Branching Layout– Wider Range of Generation Angles– Less Restriction on Segment Length

• Radial / Circular Layout– Radial Roads – Circular Roads

Generated City Results

Generated City Results

Generated City Results

Layout: Circular / RadialHighway Segments: 23Intersections: 280Road Segments: 863Buildings: 3519

Generated City Results

Layout: CheckeredHighway Segments: 68Intersections: 741Road Segments: 2239Buildings: 8959

Conclusions

• Procedural Techniques for the Creation of Virtual Cities

• City Road Layout Templates

• Preliminary Building Generation