1. Basic Model

In this first step, we will see how to define a 3D environment and populate it.

Formulation

Initialize a 3D world with a population of cells placed randomly in a 3D 100x100x100 cube.

• Definition of the cells species
• Definition of the nb_cells parameter
• Creation of nb_cells cells agents randomly located in the 3D environment size: 100x100x100.

Model Definition

In this model we define one species of agent: the cells agents. The agents will be just displayed as a blue sphere of radius 1.

species cells{                      
  aspect default {
    draw sphere(1) color:#blue;   
  }
}

Global Section

Global variable

Definition of a global variable nb_cells of type int representing the number of cells agents.

global {
   int nb_cells <-100;
}

Model initialization

Definition of the init block in order to create nb_cells cells agents. By default an agent is created with a random location in x and y, and a z value equal to 0. In our case we want to place the cells randomly in the 3D environment so we set a random value for x, y and z.

create cells number: nb_cells {
  location <- {rnd(100), rnd(100), rnd(100)};
}

Experiment

In our model, we define a basic gui experiment called Tuto3D :

experiment Tuto3D type: gui {
}

Input

Definition of a parameter from the the global variable nb_cells :

experiment Tuto3D type: gui {
   parameter "Initial number of cells: " var: nb_cells min: 1 max: 1000 category: "Cells";	
}

Output

In our model, we define a display to draw the cells agents in a 3D environment.

output {
  display View1 type:opengl {
    species cells;
  }
}

Complete Model

This model is available in the model library (under Tutorials > 3D) and the GIT version of the model can be found here Model 01.gaml

model Tuto3D

global {
  int nb_cells <-100;	
  init { 
    create cells number: nb_cells { 
      location <- {rnd(100), rnd(100), rnd(100)};       
    } 
  }  
} 
  
species cells{                      
  aspect default {
    draw sphere(1) color:#blue;   
  }
}

experiment Tuto3D  type: gui {
  parameter "Initial number of cells: " var: nb_cells min: 1 max: 1000 category: "Cells" ;	
  output {
    display View1 type:opengl {
      species cells;
    }
  }
}