Constraints (drillholes)
It is possible to view and interact with a subset of the drillholes in a database by applying constraints. Only the holes that satisfy the constraints are displayed when Display drillholes is used. To use the constraints functions effectively, you must understand the concept of a constraints stack.
The Add new constraint, Remove last constraint, and Clear all constraints menu items each operate on the drillhole constraints stack.
The drillhole constraints stack is a list of all of the constraints that have been defined using the Add new constraint function with the oldest, or first constraint that was added at the bottom of the stack, and the most recent constraint at the top of the stack. You can add as many constraints to the stack as necessary to obtain the set of drillholes that you require. Each new constraint added to the stack is added to the existing constraints on the stack to determine which drillholes are drawn.
Each time you use the Remove last constraint function, the constraint which is at the top of the stack is removed and the drawing reverts to the way it was before the constraint was added.
Continual use of the Remove last constraint function ultimately removes all constraints from the stack, and then the entire database is displayed.
The Clear all constraints function causes the entire constraint stack to be deleted. This produces the same result as repeated use of the Remove last constraint function to remove all constraints from the stack except that it is much faster.