Projection orthographics

Hello !!! I have a concern with my matrix of projection
I have two section of wall with an angle of 90° when I am in the sight of face and that I carry out a rotation of 90 to my camera and well I do not see the second section of wall
whereas in another sight (front view with a skew for impression of depth) and well I see it!!! it is really strang !!!

it is similar for the sight of top I does not see anything!!!
Thank you!!!

Hi !

Near/far clipping planes ?

Backfacing triangles ?