Film stress can be a technology problem for fabrication. To reduced stress in wide metal areas small slots are insert. This feature does such slot insertion for all selected shapes. All required parameters can be set in an dialog. (introduced with version 20140110) If tzhe choosen partameter would require more than 20.000 slots no modifications are made, the resulting polygons will no longer be handable afterwards. In that case please split the shapes before by using the cut feature.