EdgeCAM supports a number of different entity types as detailed in the reference section of this document. The EdgeCAM database is the data structure that contains all this information.
Each entity is given a unique number when created and PCI may reference each entity by this number.
However, this number may change in subsequent worksession, depending on which defaults file has been loaded and which entities have been deleted. This makes writing PCI macros that reference existing database entities quite difficult. PCI system variables do give access to the number of entities in an empty part and the total number of entities present in the database at any one time (&BASEENT and &NEXTENT).
To simplify this problem, EdgeCAM also allows entities to be accessed by an entity name, for example by using the %ADDENTNAMEDIG directive. The entity name is always unique and does not change. Entity names of up to eight characters are supported. If the name has already been used in the database, EdgeCAM generates a unique name by appending ‘.n’ (where n is a number between 1 and 999) to the specified name.
Most entity types can be digitised at either end. A direction flag indicates which end of the entity has been digitised. With a line entity, the direction flag will be zero if the start of the line is digitised, or 1 if the end of the line is digitised.
When creating PCI macros to refer to existing geometry, we recommend that you name the geometric entities.
About Handles
A ‘Handle’ is the name of a memory storage area. This area is where all digitised information for the PCI is placed, including any geometric or toolpath entities created when the PCI is executed.
The default name given to this handle in the PCI commands is ‘gdh1’. You can edit this to any desired name.