# Research Results

During my research I examined the logic of the L-Systems. I studied the rules the history and the use of the L-Systems. The aim of my research was trying to get some different visual effects instead using it for modelling trees as usual. After, practicing on tree and plant modelling I started to draw some sketches of patterns and imitate them in Houdini L-System SOP. The Results were convincing. I drew some basic shapes like cubes triangles and other geometric shapes and then tried to make them grow procedurally. During this process, I got experienced in rules and tried to model more complex systems.

The Following animations are some examples for the result of my research.

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01Growing Cubes

Lsystem |
Growing Cubes |

Premise |
F[&A]+F[&A]+F[&A]+F[&A] |

Rule 1 |
A=;F+FB |

Rule 2 |
B=F^FZ |

Rule 3 |
Z=F[&A]+F[&A]+F[&A]+F[&A] |

Angle |
90 |

- I Put some branches to the initial string to be able to create the cube geometry. (Volumed with PolyWire SOP instead of using the Tube mode of the L-System SOP in order to get a clean geometry)

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02Houdini Creature 01

Lsystem |
Houdini Creature 01 |

Premise |
F[&A]+F[&A]+F[&A]+F[&A] |

Rule 1 |
A=;F+FB |

Rule 2 |
B=F^FZ |

Rule 3 |
Z=F[&A]+F[&A]+F[&A]+F[&A] |

Angle | 90 (Animated) |

Angle Scale | Sin($F*4)/3 |

Generations | 5 |

- As it can be seen from the Rules they are exactly the same rules with the growing cubes example. However, I animated some parameters and values and add some expressions to get a different effect. The Result was surprisingly different from the 1st example.(Rendered with metaballs to get a jelly look)

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03Houdini Creature 02; Dynamic

Lsystem |
Houdini Creature 02 |

Premise |
F[&A]+F[&A]+F[&A]+F[&A] |

Rule 1 |
A=;F+FB |

Rule 2 |
B=F^FZ |

Rule 3 |
Z=F[&A]+F[&A]+F[&A]+F[&A] |

Angle | 90 (Animated) |

Angle Scale | Sin($F*4)/3 |

Generations | 5 |

For the sake of, getting cool effects, I decided to combine the L-system animations with Dynamics. I piped the previous animation into Dynamics and add some strings to the creature. The effect that I achieved was an organic looking underwater creature.

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04L-Machine

Lsystem |
L-Machine |

Premise |
^FFFF[&A]+FFFF[&A]+FFFF[&A]+FFFF[&A] |

Rule 1 |
A=FFFX |

Rule 2 |
X=&F[B]F[C]FF[D] |

Rule 3 |
B=+ffF[G] |

Rule 4 |
C=+F[G] |

Rule 5 |
D=^(b)T(e)FF+F-FK |

Rule 6 |
G=&(c)F(d)J |

Angle |
90 |

Variable b |
20 |

Variable c |
sin($FF*20)+90 |

Variable d |
sin($FF*10)/9 |

Variable e |
sin($FF*10)*7 |

This System includes a little bit more rule than the previous ones. There is also Gravity factor involved and animated by e variable. Creating variables in the system gives many flexiblities in terms of having the control of the system.

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05Cage

Lsystem |
Cage |

Premise |
^F+(b)F[A]+(b)F[A]+(b)F[A]+(b)F[A] +(b)F[A]+(b)F[A]+(b)F[A]+(b)F[A] +(b)F[A]+(b)F[A]+(b)F[A] |

Rule 1 |
A=&(c)FX |

Rule 2 |
X: t<=3 =&FA |

Rule 3 |
X: t>3 & t<5 =B |

Rule 4 |
B=^F+(b)F[A]+(b)F[A]+(b)F[A]+(b)F[A] +(b)F[A]+(b)F[A]+(b)F[A]+(b)F[A] +(b)F[A]+(b)F[A]+(b)F[A] |

Rule 5 |
X: t>6 =C |

Rule 6 |
C=J |

Angle |
90 |

Variable b |
if($F<74, sin($FF*5)*30,5.20945 |

Variable c |
45 |

- At this animation I used a lot of expression to get the slide and the other effects. Besides I had to use some L-System based if statements [ ex: X: t>3 ( if iteration count greaterthan 3 ) ]and external Houdini statements to stop the growing at some point and start another type of growing. And at the end of the animation I add some fruits ( J ) by using leaf inputs of the L-System SOP. Lastly, with a quick duplication I achieved a wierdly growing cage effect.

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Conclusion:

As a conclusion, I realized that L-Systems will be a very powerful tool in terms of creating motion graphics style effects. Besides the architectural and plant side of the L-Systems it will definitly be a good solution to achieve various effects in Films and Commercials industry.