R                      x,                   y,                   z

   O  =                   1,                   0,                   0
   O' =              cos(t),                   0,              sin(t)

   F  =                   D,                   0,                   0

  Vz  =                   0,                   0,                   1
  Vz' =       cos((pi/2)-t),                   0,       sin((pi/2)-t)
  Vz' =              sin(t),                   0,              cos(t)

  Vg  =           (2^1/2)/2,          -(2^1/2)/2,                   0
  Vg' =    cos(t)*(2^1/2)/2,          -(2^1/2)/2,   -sin(t)*(2^1/2)/2

  Vd' =    cos(t)*(2^1/2)/2,           (2^1/2)/2,   -sin(t)*(2^1/2)/2

 Vzg  =                   0,          -(2^1/2)/2,           (2^1/2)/2
 Vzg' =    sin(t)*(2^1/2)/2,          -(2^1/2)/2,    cos(t)*(2^1/2)/2

 Vzd' =    sin(t)*(2^1/2)/2,           (2^1/2)/2,    cos(t)*(2^1/2)/2


 pfg' =                   D,           -D/cos(t),    -D*sin(t)/cos(t)
 pfg' =                   D,           -D/cos(t),           -D*tan(t)

 pfd' =                   D,            D/cos(t),           -D*tan(t)

 pfz' =                   D,                   0,            D/tan(t) si t>0
 pfn' =                   D,                   0,           -D/tan(t) si t<0

pfzg' =                   D,           -D/sin(t),            D/tan(t) si t>0
pfzd' =                   D,            D/sin(t),            D/tan(t) si t>0


   H  :                   0,                   0,         z=-D*tan(t)


D=50
t=15°