Search Limits Overview

When you Compute Blocks in RocTunnel3, by default, the block engine will consider the entire model. If you do not need to search the entire model or you wish to focus a search on a particular area, you can do this with the Search Limits options.

The Search Limits options allow you to narrow the search area to specific areas of the excavation. Three methods are available:

• Add Search Limit by Box - This allows you to define 3D boxes to be used as search limits
• Add Search Limit by Arbitrary Volume - This allows you to define any 3D volumes to be used as search limits.
• Auto Search Limits - RocTunnel3 automatically determines the 3D box regions where joint cluster(s) exist within the External geology.

Search Limit Type

Define search limits as inclusion or exclusion zones. Two types of Search Limits can be specified for Add Search Limit by Box and Add Search Limit by Arbitrary Volume:

• Completely Inside - only blocks which are completely INSIDE the search limit volume will be analyzed
• Completely Outside - only blocks which are completely OUTSIDE the search limit volume will be analyzed

Blocks on Non-terrain Surface are Considered Invalid

The Blocks on Non-terrain Surface are Considered Invalid option is only applicable to Completely Inside Search Limit Type. The non-terrain surface is automatically determined by RocTunnel3 to be the sides and bottom of the extents of the External geology. By default, RocTunnel3 will consider all blocks which touch the non-terrain surface as invalid in order to prevent blocks from exposing to the excavation surface and being able to be removed from these areas. In cases where the non-terrain surface determination is not as intended (due to constraints in geometry such as vertical or overhanging excavation faces), the user can override the non-terrain surface by creating a Search Limit by Add Search Limit by Box or Add Search Limit by Arbitrary Volume:

1. Set Search Limit Type = Completely Inside.
2. Deselect Blocks on Non-terrain Surface are Considered Invalid checkbox.

Any blocks which are inside the Search Limit and touching the non-terrain surface are considered valid.

The user should also be cautioned that the definition of Search Limits may result in the omission of otherwise important blocks.