Restrict with DTM

Select the Restrict with DTM option to decompose blocks based upon whether the blocks are above or below an existing DTM. No blocks will be created outside of the DTM.

A "DTM" page is available on the Navigation tree at the left of the Create Blank Block Model form:

Each block centre point in the block model file is projected onto the DTM. The Z value of the centre point is compared to the Z value of the DTM. The value written to the Code field for that point depends on whether the point is above or below the DTM.

DTM

Select a wireframe type, typically DTM, then click on the List icon to select the Name of the DTM that will be used to restrict the block model.

Volume Factor

By default, the Create Blank Block Model function performs a volume factor calculation.

Volume factor field

Enter the name of the Volume factor field. The portion of each block that falls above or below the DTM will be written to this field.

Sub-blocks

East, North, Z

If you selected Sub-blocks as the sub-blocking method; directly enter or select from the drop down lists, the number of blocks in each direction, into which the block will be subdivided.

Although any number up to 64 can be directly entered, the factor of two (2) numbers in the drop down lists will provide better performance. The more sub-blocks there are, the more accurate the assignment will be; but be aware that sub-block numbers will create a larger file, leading to exponentially longer run times. The smaller the number of sub-blocks, the smaller the file and the better the performance.

The maximum number of sub-blocks is 64, which can be selected from the drop down lists. However, as the application will warn, a maximum of 16 sub-blocks is recommended. A warning will not be displayed for any factor of two number up to 64.

Note: Block size should be REAL type (double precision), as the display precision may be important to see differences.

Code Values

Code Field

Specify the name of the Code field and the Above values and Below values that will be written to the Code field to denote whether each block falls below or above the DTM.

Delete Above/Below DTM

Specify whether blocks above and/or below the DTM will be deleted from the blank output file.

Assign Factors

If you selected the Volume factor option, specify whether volume factors will be written to those blocks above the DTM, or below the DTM.