Based on the technology layer settings all electrical connected shapes are internal marked, so that a node highlighting, a net list extraction or a LVS can be done. On big design this operation may take some time. Therefore in the setup it can be adjusted whether this feature is triggered automatic or just manual.
As mentioned before the result is used to hightlight a node via NodeMode and to perform the LVS. This build function is incompatible to cellrefarray, so all relevant array are flatten to cellrefs.
Optional listed shape datatypes can be ignored during building the electrical connections. Shapes with the listed datatype will never connect two nodes. E.g. this can be use to avoid a short at a resistor made by a metal or poly layer. The ignore datatypes need to be set in the SetupDialog. This option was introduced with version 20150421.