Overview

Block models can be manipulated to derive new variables by calculation. Variables can also be manually added, modified or deleted.

Scripts with conditional "if" statements can be used to develop complex calculations. These statements are stored in an ASCII script file ( .bcf ). Examples are provided in Appendix A.

The Index option allows the creation of a spatial index to a block model. We recommend that you use this option as it decreases the access time to the blocks. Keep in mind, however, that an equal amount of free disk space is required when indexing a 'Classic' block model, for example, if the block model is 4Mb in size, then you will need to have a minimum of 4Mb free disk space in order to perform the index procedure. No extra disk space is required when indexing an 'Extended' block model.

Format Comparison
	Classic	Extended
Data allocation	All data must be allocated when the block model is constructed.	No data is stored when a block model is created. Disk space is dynamically allocated when values are stored into blocks.
Block model blocks	Restricted to 2x109blocks.	Can exceed 1018blocks
Indexing	You require an amount of free disk space that is equal to the size of the actual block model. For example, if the block model is 4Mb in size, then you will need to have a minimum of 4Mb free disk space in order to perform the index procedure.	No extra disk space is required in order to perform the index procedure. In a regular extended model the index is not stored, but is implied, so the model is always indexed. In a sub-blocked extended model the index is stored in such a way that it does not need to be rewritten, so the model remains indexed.
Miscellaneous	Models can be created very quickly. Model may contain a large number of blocks, well in excess of 4 billion blocks. Variables may be added and removed quickly. Disk space is only used for block values which are stored.

Tip:   For faster access to the block mode. we recommend that a block model is indexed prior to viewing.