4.1.1. Create OcTree Mesh

OcTree meshes used in the E3D version 2 tiled code are created using the program create_octree_mesh_e3d_v2_tiled.exe. The program creates a global OcTree mesh (on which the model lives) and a set of local OcTree meshes (referred to as ‘tiles’) based on survey geometry. Parameters necessary for creating the OcTree meshes are set in the input file; referred to here as octree_mesh.inp.

To generate the OcTree meshes, open a command window. Type the path to the code create_octree_mesh_e3d_v2_tiled.exe, followed by a space, followed by the path to the input file.

../../_images/run_create_octree.png

The program create_octree_mesh_e3d_v2_tiled.exe creates 5 output files:

  • 3D_mesh.txt: the underlying regular tensor mesh corresponding to the global OcTree mesh. This mesh is comprised of the smallest cell size and is very large (>> 1M cells). As a result, it is unwise to plot this mesh.

  • 3D_core_mesh.txt: a 3D regular tensor mesh defining the core region of the global OcTree mesh.

  • octree_mesh.txt: the global OcTree mesh.

  • active_cells_topo.txt: an active cells model on the global OcTree mesh which defines the topography. Cells are active (underground) if assigned a value of 1 and inactive (in the air) if assigned a value of 0.

  • octree_small_mesh.dat: a binary data file containing the local forward meshes for all transmitters.

  • create_octree_mesh_e3d_v2_tiled.log: log file