Now in code: if (this->Points) { double x[3]; this->Points->GetPoint(lv); this->Points->SetPoint(v, x); this->Points->SetNumberOfPoints(lv); } Should change to: if (this->Points) { double x[3]; this->Points->GetPoint(lv,x); this->Points->SetPoint(v, x); this->Points->SetNumberOfPoints(lv); } Best regards, Naszta