Types of Undefined Edge: The symbol element + (plus) indicates permitted excess material, i.e. passing.The symbol element – (minus) indicates required material removal, i.e. undercut.The symbol element ± (plus or minus) indicates permitted excess material or material removed, i.e. an undercut or a passing. This can only be used with an indication ofsize Table 1 … Continue reading ISO 13715 Technical product documentation — Edges of undefined shape — Indication and dimensioning