釋氏要覽 1.283

1.283

准律有十種。不越布絹紬三也。須是厚熟緻（密也）者○五百問經云。三衣得用生絹作否答一切生物但不現身者得（律中遮此經開）。

According to the Vinaya, there are ten kinds, not exceeding the three: cloth, silk, and pongee. They must be thick, well-prepared, and dense (tightly woven). / The Five Hundred Questions Sūtra asks: "May the three robes be made using raw silk?" It answers: "All raw animal products, as long as they do not show their living form, are permitted" (the Vinaya prohibits this; this scripture permits it).