notes for research gathering on 2008-11-28 at FoAM related » project groworld

1. form → (…)
2. function → more involved

“The power of L systems goes beyond their capability to generate realistic images of plants […] they also provide a model of their operation, including processes such as tropisms, abscission, signal propagation, or watering.”

–Roberto S. Ferrero

There is a number of applications in which L systems plays an important role as a biological model:

1. structural models of trees integrated in more complex forest ecosystem simulations,
2. identifying plant response to insect attack,
3. design of new varieties of plants,
4. reconstruction of extinct plant species,
5. crop yield prediction,
6. classification of branching patterns in inflorescences,
7. simulation of fungal growth, or
8. computer aided learning for farm managers.“

via. Roberto S. Ferrero

Following the structure of “algorithmic beauty of plants”…

• deterministic & context free (simple) l-systems

• variations & randomness

• symbol replacement dep. on context, or previous states
• can be used to model signal propogation

• elements can be parameterised, eg. segment lengths
• continous development, motion, growth or diffusion

• L-systems provide good structural models, how can we model growth and changes over time?
• multi-level models
  • partial l-system (structural - non deterministic)
  • l-system schemata (control mechanisms, resolve n.d., temporal aspects)
  • complete l-system (geometric info, growth rates/branching/appearance)
• compound flowering structures (inflorescences)
• Phyllotaxis. In order to describe the pattern of florets (or seeds) in a sunflower head, Vogel proposed the formula φ=n∗137.5◦, r=c√n {cf. ABOP 4.1}
• surface models (ABOP 5)
  • the shape as well as size of plant organs may change over time
  • leaf types

• The original formalism of L-systems provides a model of development that is discrete both in time and space.
  • the model states are known only at specific time intervals.
  • spatial organisation is finite
  • Parametric L-systems remove the limits imposed by discrete spatial representation
    • assign continuous attributes to model components
    • model states are still known only in discrete time intervals.

• expression of production rules is still discrete, yet each cell has its own 'lifetime' as specified in the production rule
• symbols represent cells that elongate during their lifetime and divide upon reaching terminal age.
• effect of aging, and gradual development can be modeled
• 'young' cell can be replaced by mature form → fruits

• “Visual Models of Plants Interacting with Their Environment” Radomír Mech and Przemyslaw Prusinkiewicz
• [x.ref]

• what advantages/disadvantages over l-systyems?
• why another abstraction?

• benefits
• tradeoffs

• http://www.blprnt.com/processing/cherrytree/
• http://www.blprnt.com/processing/birchtree/
• karl sims - panspermia (1990) http://www.youtube.com/watch?v=AgeuRukfZLE from ~1:00 onward

• http://openalea.gforge.inria.fr/
• https://team.inria.fr/virtualplants/software/