What is L-studio?

L-studio is Windows software for creating simulation models and performing virtual experiments using L-systems. It consists of:

two L-system–based simulators, cpfg and lpfg;
a set of sample models, primarily of plants, each stored as an L-studio object;
a graphical browser for organizing and accessing objects on local and remote machines;
a series of editors and other modeling tools for creating and modifying objects; and
a library of environmental programs which simulate environmental processes that affect plant development.

Schematic diagram of the components of L-studio

The simulators cpfg and lpfg

At the heart of L-studio are the simulator programs cpfg and lpfg. These programs take as input an L-system file, usually along with one or more related files, comprised in an L-studio object. The simulators produce a visual representation of the model. Depending on the L-system, the models may be animated and/or interactively manipulated. Optionally, the simulators may also produce various output data files. cpfg and lpfg share a common interface (L-studio proper). cpfg is more suitable for the rapid creation of simple models. lpfg is particularly useful when creating complex models.

L-studio objects

An L-studio object is a set of files kept together in a common directory. Each of these files specifies one component of the object; some of these files are required, and some are optional.

The L-system file (*.l) is a text file containing the L-system which will serve as the primary input to cpfg or lpfg. Every object must have an L-system file.
The view file (*.v) specifies drawing and rendering options, as well as other general parameters for cpfg or lpfg. Every object must have a view file, though it may be empty.
The animation file (*.a) contains parameters which define how cpfg/lpfg will animate the simulation. Every object must have an animation file, though L-studio will set up a default file automatically.
A color map (*.map) defines a 256-color palette which is used by the simulator to draw the model in colormap mode.
Alternately, a material file (*.mat) can be used if the model is rendered with shaded polygons. Every object must have either a color map or a material file.
Surfaces (*.s) are user-defined Bezier surfaces which can be incorporated into 3D models; for example, to capture the shape of leaves or flower petals.
Contours (*.con or *.cset) are used to describe the axis or cross-section of elongated limbs, such as stems.
Functions (*.func or *.fset) are graphically-defined functions of a single variable that can be incorporated into L-system models.
Control panels (*.pnl) are used to interact with the model by manipulating parameters, or turning model features on or off.
An environmental communication specification file (*.e) defines how the model will communicate with an external environmental program (*.exe). The environmental process may optionally use additional input files.
The object description (description.txt) is a text file which is typically used to describe the object, how it works, how it was constructed, and so on. All objects must have a description, though it may be empty.
The object specification files (specifications and LSspecifications) are text files which define object-specific parameters and are used by L-studio to determine how to handle each particular object. Under the UNIX-based system vlab, the specifications file is mandatory; however, neither file is required in an L-studio object.

All L-studio objects will contain an L-system, a view file, an animation file, an object description, and either a color map or material file, although these may be empty or contain nothing more than default values.

The object browser

The object browser is a tool for accessing and navigating databases of L-studio objects. An object database is stored in an object oriented file system, or oofs. (This system is object oriented because it uses a prototype-extension paradigm; if an object is a refinement (extension) of another (the prototype), then the extension is stored in a subdirectory of the prototype.) Using the browser, you can navigate the oofs and open objects in L-studio.

Modifying an object in L-studio

When an object is opened in L-studio, it is copied to a temporary location called the lab table. The lab table version can be experimented upon in any way, and the changes will not be reflected in the original object until the open object is saved.

When on the lab table, an object's component files can be modified with L-studio's integrated editors. L-studio has tools to edit almost all of the files listed above: text files such as the L-system or object description; 2D or 3D shape files, such as surfaces, contours, or functions; color files; panels; and options files, like the animation file or the object's specifications.

Environmental programs

Environmental programs are one object component that is not edited in L-studio. Instead, these environmental programs must be written in an external programming language, and the resulting executables placed somewhere accessible to the object: either in the object's directory, or in a central environmental program location. L-studio comes with several useful environmental programs: see the User's manual for environmental programs for more information on them and how to use them.

More information

More information about modeling using L-systems can be found in the CPFG User's Manual and the LPFG user's manual. The manuals are available in PDF format:

CPFG user's manual (1.45 MB)
LPFG user's manual (235 KB)
User's manual for environmental programs (310 KB)
Extensions to the graphical interpretation of L-systems based on turtle geometry (1.04 MB).