UBC to Voxel

Use the Voxel > Conversions > UBC to Voxel menu option (geogxnet.dll(Geosoft.GX.VoxUtils.ImportUBCToVox;Run)*), to import UBC 3D Model & Mesh files to a Geosoft Voxel.

UBC Mesh Tools 3D Model to Voxel dialog options

Output voxel	Specify the name of the Geosoft Voxel file to generate (.geosoft_voxel). Script Parameter: IMPORTUBCTOVOX.OUTPUT_FILE
Model file	Browse to select the UBC Model file to import. Script Parameter: IMPORTUBCTOVOX.MODEL_FILE
MSH Header file	Specify the Mesh file (*.msh) containing a description of the 3D mesh. See below for the format. Script Parameter: IMPORTUBCTOVOX.MSH_HEADER_FILE
Dummy value	Specify a value to be interpreted as dummy in the import. Script Parameter: IMPORTUBCTOVOX.DUMMY_VALUE (default -9.0) There is no fixed dummy value in UBC mod files; it is normally set as -9.0, but it can be -90.0– for instance if there is real data smaller than -9.0.s.

Coordinate System

The Coordinate System dialog allows you to specify the correct coordinate system information (Datum and Projection Method) for the incoming UBC 3D Model/MSH file.

Script Parameters:

IMPORTUBCTOVOX.IPJ_NAME
IMPORTUBCTOVOX.IPJ_DATUM
IMPORTUBCTOVOX.IPJ_METHOD
IMPORTUBCTOVOX.IPJ_UNITS
IMPORTUBCTOVOX.IPJ_LOCALDATUM

Application Notes

*The GX.NET tools are embedded in the geogxnet.dll file located in the "...\Geosoft\Desktop Applications \bin" folder. If running this GX interactively, bypassing the menu, first change the folder to point to the "bin" directory, then supply the GX.NET tool in the specified format. See the topic Run GX for more details on running a GX.NET interactively.

If a 3D Viewer is open during the import, then the output voxel will be displayed in that 3D view. Otherwise, the output voxel will be displayed into a new Voxel Viewer window. If the output voxel does not display, open the Advanced Settings dialog (Project > Settings > Advanced) and under the Voxel Settings section, check if the Display Created Voxels option is set to "True".

MSH Header File Format

This file contains the 3D mesh which defines the model region.

The mesh has the following structure:

NE NN NV

E0 N0 V0

?E1 ? E2 ... ? ENE

? N1 ? N2 ... ? NNN

?V1 ? V2 ... ? VNV

NE Number of cells in the East direction.

NN Number of cells in the North direction.

NV Number of cells in the vertical direction.

E0, N0, V0 Coordinates, in meters, of the southwest top corner, specified in (Easting, Northing, Elevation).

Model File Format

Model files consist of a total of NE*NN*NV values - one per line.

Example:

-9.0000000e+000

1.0607292e+001

1.0642567e+001

1.0762947e+001

1.0782325e+001

1.0803412e+001

1.0837755e+001

etc...

File structure of model .sus:

sus1,1,1

sus1,1,2

sus1,1,NV

sus1,2,1

susi,j,k

susNN,NE,NV

susi,j,k susceptibility at location [i j k].

[i j k]=[1 1 1] is defined as the cell at the top-south-west corner of total number of lines in this file should equal NN NE NV, where NN is the in the North direction, NE is the number of cells in the East direction, and NV cells in the vertical direction. The lines must be ordered so that k changes the 1 to NV), followed by j (from 1 to NE), then followed by i (from 1 to NN).

The dummy value is -9.0, and is automatically converted to a Geosoft dummy on import.

The above descriptions are derived from the following document: MAG3D

A Program Library for Forward Modelling and

Inversion of Magnetic Data over 3D Structures

VERSION 3.0

Developed under the consortium research project

JOINT/COOPERATIVE INVERSION OF

GEOPHYSICAL AND GEOLOGICAL DATA

UBC–Geophysical Inversion Facility

Department of Geophysics and Astronomy

University of British Columbia

Vancouver, British Columbia