Los Alamos Grid Toolbox

LaGriT (Los Alamos Grid Toolbox) is a library of user callable tools that provide mesh generation, mesh optimization and dynamic mesh maintenance in two and three dimensions. LaGriT is used for a variety of geology and geophysics modeling applications including porous flow and transport model construction, finite element modeling of stress/strain in crustal fault systems, seismology, discrete fracture networks, asteroids and hydrothermal systems.

The general capabilities of LaGriT can also be used outside of earth science applications and applied to nearly any system that requires a grid/mesh and initial and boundary conditions, setting of material properties and other model setup functions. It can also be use as a tool to pre- and post-process and analyze vertex and mesh based data.


  • Representation of 2- and 3-dimensional complex geometries
  • Unstructured triangle/tetrahedral and structured or unstructured quadrilateral/hexahedral meshing
  • Model set-up including assigning material properties, boundary conditions, and initial conditions
  • Adaptive mesh refinement, smoothing, and optimization
  • 2D and 3D Delaunay triangulation conforming to complex geometry
  • Output for solver packages including specialized format for FEHM, Amanzi/ATS, PFLOTRAN, and TOUGH2
  • Interactive command line, batch input file, or embedded in Fortran/C interfaces (no GUI)
Image link to first example graphic
Image link to first example graphic
Image link to first example graphic

LaGriT Distribution and Documentation

Auxiliary LaGriT Programs

The PyLaGriT module allows LaGriT commands to be accessed interactively and in batch mode from Python. Common and useful meshing workflows are combined into a set of higer level python calls which also enables loops and better parameter control.
VORONOI is a parallel and scalable program for writing Voronoi tessellation control volumes (connectivity graph, control volume areas/volumes) compatible with: FEHM, PFLOTRAN, TOUGH2, and HDF5. The Voronoi software requires a PETsc library.
GRIDDER: is rectangular grid generator that creates structured grids in a format used by FEHM.
Software often used with LaGriT input and output files include:
AVS (Advanced Visual Systems)
GMV (General Mesh Viewer)

LaGriT Applications

dfnWorks is a parallelized computational suite to generate three-dimensional discrete fracture networks (DFN) and simulate flow and transport. dfnWorks creates high-fidelity three-dimensional networks dfnGen, which combine FRAM (the feature rejection algorithm for meshing) methodology to stochastically generate three-dimensional DFNs with the LaGriT meshing toolbox to create a high-quality computational mesh representation.
TINerator takes advantage of LaGriT mesh commands combined with GIS data to triangulate and stack a 3D mesh.
LANL Meshing Projects main page.
Gallery of selected meshing project images.
SFWD-GDSA Geologic Applications Project and workflow web pages
Examples for GDSA Geologic Applications GitHub repo.
VoroCrust collaboration with Sandia GitHub repo.