As the geometric condition of illumination and light reception for transparent object, JIS Z8722 standard recommends the following 4 cases.
[Figure. 5] Geometric condition of illumination and light reception for transparent object (e)
[Figure. 6] Geometric condition of illumination and light reception for transparent object (f)
[Figure. 7] Geometric condition of illumination and light reception for transparent object (g)
[Figure. 8] Geometric condition of illumination and light reception for transparent object (h)