Itasca Software Guide

All Itasca software is built on a common strata of elements at the foundation of each program—regardless of the numerical method or the elements the program uses. Consequently, whether using DEM software such as 3DEC or PFC, or using continuum software such as FLAC3D, there will be many processes, utilities, and capabilities that are common to all of them.

All the material in this section focuses on those common apparatuses, which permeate every aspect of the software, from modeling methodology to implementation of commands to calculation scheme to user interface design to the techniques for model design, processing, and output. And more. The sub-sections listed below cover each of these areas as follows.

Modeling Methodology

This section provides a high level guide to numerical modeling, providing a recommended approach to the process and a discussion of specific considerations that may impact model design and program performance.


This section surveys the scientific context of the program. It enumerates conventions regarding notations, command syntax highlighting, sign conventions, system of units, precision limits. It also introduces the calculation cycle, physical forces at work in the model (energy, stress and strain), and an introductory look at the components that are used to create models (zones, balls or clumps, structural elements, blocks, etc.).

User Interface

This section describes most of the numerical model development environment provided by the program. The material follows the order the user encounters each aspect of the program interface along the modeling process: program start and configuration, project creation, data file and command processing, plotting, solving, and results storage. This section can be considered a general user’s guide to the program.

Common Commands and FISH

This section is the reference for all commands and FISH functions that are commonly available in all Itasca numerical modeling codes. The specific sets of commands for PFC, FLAC3D, and 3DEC are referenced in PFC Model Objects, FLAC Commands, FISH, and Workspaces, and 3DEC Commands and FISH, respectively.

Constitutive Models

The mechanical constitutive models available in FLAC3D and 3DEC range from linearly elastic models to highly nonlinear plastic models. The basic constitutive models are described in this section. Each model description includes a short discussion of the theoretical background and simple example tests.

Structural Elements

Descriptions of the seven types of structural elements provided in FLAC3D and 3DEC, the components constituting them, the theory and background of the structural element formulation, and example applications illustrating use of structural elements in models are all provided in this section.

Commands and FISH References





  • FISH Scripting Reference for the general reference on FISH;

  • FISH Functions for an index of all functions built directly into the FISH language (that are not associated with the set found with the common commands (see above)).

  • Python Scripting for the general reference on Python in Itasca software.

Things you need to know: 1. the program is command based 2. the program is state based 3. there is incomplete overlap between commands and UI 4. the program is many-in-one 5. there is always an active pane 6. the tools are responsive to which pane is active