✔ 最佳答案
What is structural line?
(1) Structural lines can mean the lines in a drawing that show the structure of the drawn object. eg
圖片參考:
http://t3.gstatic.com/images?q=tbn:OdBXwZ4P9iEHPM:http://jennifervanbuskirk.com/wp-content/uploads/2009/03/still-life-study-7-798x1024.jpg
(2) The Structural Line (SL) is the meeting line of two structural planes (SPs). It has a length but has no width nor depth. It is one of the structural space element shown below.
eg
圖片參考:
http://www.sunyuli.com/mybooks/images/index_img_1.jpg