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Landscape Generation with

L-Systems

By: David ColeSupervisor: Jon McCormack

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Project Overview

What? Model with visual realism the

interaction between plants and their environment.

Why? Has a large range of applications

Architectural and Design Conservation of an ecological system Video games

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Background Information

EcoSys An integrated system that generates

realistic environmental images based upon user specified input. Plant densities and terrain formation.

Used L-Systems to generate the plant models.

Main focus visual realism

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Example:

By: Oliver Duessen (and Researchers) – Realistic Modelling and Rendering of Plant Ecosystem (River Scene)

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Methodology

Terrain Generation Resource Allocation

Plant Distribution and Growth Scene Generation Plant/Trees Modelling Scene Rendering

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Terrain Generation Generate visually interesting terrain. Terrain generated with a midpoint displacement algorithm “Diamond Square”. The algorithm operates as by sub-division an area and displacing the terrain by a random amount.movies\terrain\terrain2.avi

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Resource Allocation Resources are allocated to each grid point.

Resources Include: Water Carbon Minerals

Try and emulate varying soil types within the terrain. Examples

Water Carbon Phosphors Potassium Calcium

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Plant Distribution

Plant competition is simulated with a modified Firbank and Watkinson algorithm. Each plant presented by a sphere. If 2 spheres intersect, then they are competing. movies\plant animations\plant_spread2.avi movies\plant animations\plant_spread1.avi

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Plant Growth

Each plant acquires resources from terrain and sun. Carbon dioxide, minerals and water extracted from the ground. Sunlight calculated based upon plants elevation and intersection. If an intersection occurs:

Otherwise the plant receives the a proportion of the sun (depending on the number of leaves for the plant).

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Plant Modelling

Performed using L-Systems. L-Systems are a rewriting process that generates a string of characters based upon a set of production rules.

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L-System Example:

Axiom = F

Production Rule: F -> FF+[+F-F-F]-[-F+F+F]

1st Iteration – String = F

2nd Iteration – String = FF+[+F-F-F]-[-F+F+F]

3rd Iteration – String = FF+[+F-F-F]-[-F+F+F] FF+[+F-F-F]-[-F+F+F]+[+ FF+[+F-F-F]-[-F+F+F]- FF+[+F-F-F]-[-F+F+F]- FF+[+F-F-F]-[-F+F+F]]-[- FF+[+F-F-F]-[-F+F+F]+ FF+[+F-F-F]-[-F+F+F]+ FF+[+F-F-F]-[-F+F+F]]

• So for every F which exists in the string is replaced with FF+[+F-F-F]-[-F+F+F] for each iteration, while the characters []+- are just replaced.

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Scene Rendering

movies\final animations\final1.avimovies\final animations\secondfinal1.avi

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Conclusion Simulating mineral and water concentrations. Extension of an existing plant competition model Plant growth model Sunlight acquisition model L-System parser Plant clustering

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Future Work

More realistic terrain generation method.

Noise synthesis, FFT’s and Multi-set fractals

Complete L-System Parser Weather Model