Ignore invisible elements removes document elements from the i-net PDFC comparison basis when they make no visible contribution during display. This can include elements outside the visible page area or elements hidden by transparency, masking, or overlap.
Only after the filter is enabled can you enable Calculate actual visibility. This more accurate calculation considers clipping and overlap among other factors. It requires considerably more processing time and should therefore be considered carefully for large documents.
This option is a heuristic optimization, not a complete rendering or accessibility check. Runtime and results can vary with the structure of the PDF file.