Create Multiple Isosurfaces from Voxel

Use the Create Multiple Isosurfaces from Voxel option (geogxnet.dll(Geosoft.GX.VoxUtils.VoxelSurfaceMultiple;Run)*), to create a single geosurface file with multiple isosurfaces extracted from a single voxel. A new Geosurface file will be created and added to the Project Explorer. If a 3D View is open, the geosurface will be added to the 3D Viewer.

You can access the option from:

  • The Oasis montaj Geosurface > New > Create Multiple Isosurfaces from Voxel menu

  • The Oasis montaj 3D View >  Geosurface > Isosurface > Create Multiple Isosurfaces from Voxel menu

  • The 3D Viewer Geosurface > Isosurface > Create Multiple Isosurfaces menu

Create Multiple Isosurfaces from Voxel dialog options

Input voxel name

Select the voxel file from which the isosurfaces are to be extracted.

Script Parameter: VOXISOSURFACEMULTIPLE.INPUT_VOXEL_FILE

Output geosurface name

Select the name of the geosurface file. The default name is the same as the voxel file name.

Script Parameter: VOXISOSURFACEMULTIPLE.OUTPUT_GEOSURFACE

Surface Properties

Close isosurfaces between value ranges

Select this option to create closed shells between the minimum and maximum values. If not selected, the shells will be open.

Script Parameter: VOXISOSURFACEMULTIPLE.CLOSED_FLAG="0" (Use 0 for open, 1 for closed between value ranges)

Number of isosurfaces

Select the number of isosurfaces that will be extracted from the voxel. The default is 5. A maximum of 12 isosurfaces can be extracted.

Script Parameter: VOXISOSURFACEMULTIPLE.NUMISOSURFACES="5" (any value between 1-12 can be used, the default is 5)

Distribution

Click one of the Distribution buttons to automatically calculate the isosurface values using on a linear or a log distribution. If unchanged, Linear is used as the default distribution.

Script Parameter: VOXISOSURFACEMULTIPLE.DISTRIBUTIONTYPE="0" (Use 0 for linear, 1 for log)

Isosurface Value

The isosurface values that are to be extracted from the voxel are listed in the table. Values are calculated based on a linear or a log distribution and the number of isosurfaces above. Isosurface values can be manually changed by typing a different value into the cells.

Colour

Click a colour cell to change the display colour for an isosurface value or range of values.

Voxel Statistics

Basic statistical information about the voxel is reported under Voxel Statistics.

Colour table

Select the colour scheme for rendering the isosurfaces. If you mouse over the colour scheme entry, a tooltip will display the name of the colour table in its folder. To modify the selection, click on the colour entry and then navigate through the scheme categories.

Click Save to file to save the current colour settings to a colour table (*.ITR, *.AGG, *.ZON, *.TBL, *.LUT).

A 3D surface that passes through points of equal value is called an isosurface. Isosurfaces can be thought of as 3D contours and can be used to visualize grade shells, or other volumes of interest.

  • When using the "Open option", it is still possible to have a closed isosurface generated as the output surface, if the data forms a closed isosurface at the chosen value. Choosing the "Closed option", however, will force the output surface to be closed around any undefined areas (such as where the surface meets the edges of the voxel, or where the surface meets an area of null values). When creating multiple isosurfaces, the closed surfaces will each close around values that are between two specified values, depending on the option selected.

    • The surface is calculated using an implementation of the "Marching Cubes Algorithm" originally developed by Lorensen and Cline 1.

    Reference

    • [1] Lorensen, W.E, and Cline, Harvey E., "Marching Cubes: a High Resolution 3D Surface Construction Algorithm", Computer Graphics, vol. 21, no. 4 (1987, July).

    *The GX tool will search in the "...\Geosoft\Desktop Applications \gx" folder. The GX.Net tools, however, are embedded in the geogxnet.dll 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" folder, then supply the GX.Net tool in the specified format.

    See Also: