3DEC Features

3DEC is ideally suited to analyze potential modes of failure directly related to the presence of discontinuous features. Work with either discrete blocks, zoned continuum, or both.

3DEC provides 12 built-in zone material models, three built-in joint models, groundwater flow (solid matrix and joints), coupled mechanical-flow calculation, ground support structural elements, and a built-in scripting language (FISH) that can customize or automate virtually all aspects of program operation, including user-defined properties and other variables.

The software can be extended with four options (dynamic, thermal, Finite Element (FE) liners and blocks, and C++ User-Defined Constitutive Models) that are offered separately from the base program (see Options for more information).

3DEC offers a fully integrated development environment that includes: project management facilities, built-in text editor, automatic movie-frame generation, extensive plotting capabilities, and results monitoring.


  • Analysis of jointed rock and blocky structures based on the Distinct Element Method (DEM)
  • Built-in project management tools, text editor, automatic movie-frame generation, and extensive plotting capabilities,
  • Ideal for modeling large movements and deformations
  • Accurate simulation of fast rotating rigid blocks
  • Blocks may be rigid or automatically zoned (tetrahedral and/or hexahedral) to make deformable blocks
  • Optimized to solve problems requiring non-linear multi-physics
  • 64-bit, double-precision calculations
  • Multi-threaded algorithms with no CPU locks or additional CPU fees
  • Includes groundwater joint fluid-flow
  • Includes groundwater matrix (i.e., permeable solids) fluid-flow between fractures
  • Fluid flow may be either uncoupled or fully coupled hydromechanical
  • Proppant simulation in fluid-filled joints
  • Built-in scripting languages, FISH and Python, provides powerful user-control to parameterize, analyze, review, and modify nearly every aspect of the simulation, even during cycling
  • Track histories of model properties and results throughout the model to allow for comparison to actual monitoring and instrumentation data
  • Updated commands that are intuitive, easy to learn, and easy to apply NEW
  • Automatic conversion tool to translate 3DEC 5.2 data files to the updated 3DEC 7.0 syntax NEW

Materials and Constitutive Models

  • Includes 12 built-in constitutive material models:
    • Elastic, isotropic
    • Elastic, transversely isotropic
    • Elastic, orthotropic
    • Drucker-Prager
    • Mohr-Coulomb
    • Ubiquitous-joint (UBJ)
    • Strain hardening/softening
    • Bilinear strain hardening/softening UBJ
    • Double yield
    • Modified Cam-clay
    • Hoek-Brown UPDATED
    • Hoek-Brown-PAC UPDATED
  • Includes 8 built-in creep material models:
    • Classical (viscoelastic)
    • Burgers substance (viscoelastic)
    • Two-component power law
    • Reference creep formulation (WIPP model) for nuclear-waste isolation studies
    • Burgers-creep (viscoplastic; combination of Burgers and Mohr-Coulomb models)
    • Power-law (viscoplastic; combination of the two-component power law and the Mohr-Coulomb model)
    • WIPP-creep (viscoplastic model combining the WIPP model and the Drucker-Prager model)
    • Crushed-salt
  • Includes six built-in joint material models:
    • Elastic
    • Mohr-Coulomb
    • Continuously Yielding
    • Softening Healing Mohr-Coulomb NEW
    • Bilinear Mohr-Coulomb NEW
    • Power Law Creep NEW
  • Specify statistical distributions for material properties
  • Groundwater fluid flow analysis is included
    • Effective stress, pore pressure (water table)
    • Steady-state
    • Transient
    • Fluid flow through fractures and matrix (blocks between fractures)
    • Fracture fluid pressure and matrix fluid pressures are also coupled
    • Mechanical-fluid coupling
    • Simulate the transport and mechanical effects of proppant fluid filled joints
  • Three options are available for additional analysis:
    • Perform dynamic analysis by simulating earthquakes, vibrations, and blasts
    • Perform thermal analysis by simulating transient heat conduction
    • Create, load, and run customized (user-defined models) zone and joint models via C++ scripting

Model Construction

  • Automatic mesh generation in fully deformable blocks UPDATED
  • Build models directly from closed geometry surfaces (e.g. DXF): NEW
    • fill volume with tetrahedral blocks or
    • merge blocks to form zones within single closed surfaces
  • Cut blocks with DXF geometry NEW
  • Create blocks from VRML files NEW
  • Built-in voronoi block generator NEW
  • Built-in block zone densification for hexahedral and tetrahedral mesh refinement, including automatic octree generation from surfaces and volumes
  • New grid file format for importing and exporting blocks and zones UPDATED
  • Convert tetrahedral blocks into zones during import NEW
    • blocks with the same group name can be merged together to form multiple zones within a single block
    • this is 2-3x faster than joining
  • Automatic tunnel region generator
  • Beam, cable, and pile geometry can be imported from CAD data NEW
  • Define groups using visual and property-based ranges UPDATED
  • Built-in tools to statistically generate discrete fracture networks
  • Import 3DEC grids created by the Griddle plug-in in Rhinoceros 3D CAD
  • Block generation using primitives (face, tetrahedral, brick, drum, and prism)
  • Wall-type blocks speed up model runs as motion and wall-to-wall contacts are skipped in solution cycles

Joint Sets and Discrete Fracture Networks

  • Joint structures can be built into the model directly from geologic mapping
  • Specify continuous and discontinuous joint sets by orientation, number or spacing, origin, and persistence
  • Random seed values and statistical deviations can be utilized to create multiple realizations (examine sensitivities and risk)
  • Blocks can be hidden (and subsequently restored, similar to a layer) to limit joint cutting or joining
  • Easily define non-persistent joints (e.g., circular) and their properties
  • Blocks can be cut using Discrete Fracture Network (DFN) geometry
  • Incorporate Discrete Fracture Networks (DFNs) by specifying density (e.g., number of fractures per unit distance/area/volume) and orientation-, size-, and position-distributions for circular disks or polygons
  • Import/export both Itasca circular disk or Fracman polygon DFN data formats

Boundaries and Initial Conditions

  • Discontinuities (interfaces, joints, joint sets, and DFNs) are regarded as distinct boundary interactions between blocks; joint behavior is prescribed for these interactions
  • Stress boundary
  • Applied force (load) boundary
  • Velocity boundaries along Cartesian axes and along a normal direction
  • Structural elements for ground support include:
    • hybrid bolts NEW
    • beams
    • cables
    • piles NEW
    • shells NEW
    • geogrids NEW
    • liners (included; no longer an option) UPDATED
  • Add external infrastructure (such as dams, bridges, walls, buildings, etc.) using finite element structures (included; no longer an option) UPDATED
  • Time-varying boundary conditions
  • Couple a detailed inner model to a larger far-field model for increased solution efficiency
  • Define in-situ stresses and stress gradients
  • Includes tools to easily transfer field stresses to model stresses
  • Automatically assign in-situ stresses based on model surface topology, depth, material density, and stress-ratio values
  • Quiet (i.e., non-reflecting) and free-field boundaries (with dynamic option)

FISH Scripting

  • Provides powerful functionality to parameterize, analyze, review, and modify nearly every aspect of the simulation, even during model cycling
  • Multi-threaded FISH for much faster iterative calculations NEW
  • Built-in text editor provides command syntax error checking and context sensitive help for simpler, faster model generation UPDATED
  • FISH management control set displays the current values of FISH variables, and functions, even during cycling NEW
  • Intrinsic variables and functions (e.g., cos, round, inverse(matrix), clock, max, sqrt, urand, parse, cross, dot, pi, and more)
  • Control statements (e.g., loop, loop-while, command, if/else-if, case, pause/continue, and more)
  • The foreach object construct greatly simplifies FISH NEW
  • Intrinsic email functions to automate model notifications and result delivery (e.g., attached plots, history CSV data, and parameter values)
  • Even more variable types: Map, Matrix, Boolean, Symmetric Tensor, and Structures NEW
  • Input statements to pass data to and from FISH functions
  • Inline FISH (embed FISH calculations within a command)
  • Extra variables for blocks, zones, gridpoints, contacts, and subcontacts permit user-defined parameters to be applied, computed, or measured for each of these data structures
  • Blocks, zones, gridpoints, contacts, and subcontacts and be filtered by groups. Each data structure may be associated with multiple groups using group slots (similar to layers)
  • Error handling functions
  • Full FISH access to geometric data
  • Model data can be exported as a binary or ASCII file for use in, or exchange with, third-party software
  • Call functions at any stage of a calculation cycle (e.g., start of cycle, when contact created/detected, when sub-contact created/detected, and velocity input) using FISHCALL functions
  • Learn more about FISH

Factor of Safety Analysis

  • Automatic, fast solutions using the shear strength reduction (SSR) method and a converging bracket approach
  • May include strength properties for certain zoned material models and the Mohr-Coulomb joint model
  • Applicable for Mohr-Coulomb, Ubiquitous-Joints, Hoek-Brown, and Modified Hoek-Brown constitutive models
  • Color blocks by excess shear stress or factor of safety for a given hypothetical set of joints

User Interface

  • Common interface as Itasca's FLAC3D, PFC, and UDEC software
  • Project file and project management tools simplify organizing data files, save files, plots, etc.
  • Associated files in a project can be bundled together into a single file to easily share and archive work
  • Multiple layout configurations and customization are possible
  • Advanced ranging and filtering of model regions
  • Built-in, advanced text editor with command and FISH context coloring
  • Command-level UNDO: a record of all commands used to create a model is recorded in the SAV file, permitting the model to be rebuilt to the previous state
  • Advanced methods of filtering objects (connected to interfaces, on model surface, and by object extent)

Post Processing

  • Extensive visual plotting capabilities, including contouring on blocks, zones, and joint-surfaces; scalar, tensor, and vector plots, 3D isosurface contouring of gridpoint and zone data
  • Cut-planes, clip-boxes, and transparency settings to assist with engineering analysis and high-quality results plotting
  • Equal area and equal angle stereonet plotting of DFN joint orientations
  • Equal angle stereonet plotting of joint normal orientations and orientations of major, minor, and intermediate principal stresses
  • Export plots as PNG, DXF, VRML, SVG, or PostScript formats
  • Results visualization (property/results painting) on DXF or STL geometry
  • Easily export history results to spreadsheet-compatible CSV files
  • Import and export tables, histories, and model variable data to ASCII files
  • Automatically export a series of PNG images at regular cycle intervals to create a video-ready image set (third party software required for video assembly)
  • Ability to export plot views as data files permits favorite views (orientation, plot-items, property settings, etc.) to be saved and restored in the same, or another, model
  • Track and plot fragments (i.e., disconnected groups of blocks)

Responsive Help

  • Documentation is now in HTML format NEW
  • Access Help at the command prompt or within a data file [F1] NEW
  • Access Keyword Help [? + Enter] at the command prompt to list the possible commands/keywords given the preceding command input
  • Access Inline Help [Ctrl + Spacebar] to auto-complete commands NEW

Latest News
  • 2021 Tekne Award Work on machine learning to advance safety and efficiency in wind energy construction earned a...
    Read More
  • Itasca Software now Available for Linux Version 7 or greater of Itasca software (FLAC3D, 3DEC, PFC3D, and PFC2D) are now operable...
    Read More
  • Model Plot Contest Winners Itasca is pleased to announce the winners and honorary mentions of our Model Plot Contest...
    Read More

Upcoming Events
7 Mar
FLAC 2022 Online, Live Introductory Training
FLAC is numerical modeling software for advanced geotechnical analysis of soil, rock, groundwater, and ground support in two dimensions... Read More
21 Mar
FLAC3D 2022 Online, Live Introductory Training
This "hands-on" course includes Basic Concepts and Recommended Procedures for Geotechnical Numerical Analysis. A more focused fourth da... Read More
4 Apr
PFC 2022 Online, Live Introductory Training
This four-day course provides guidance in the use of the PFC2D and PFC3D to simulate the mechanical behavior of granular and solid mate... Read More