We choose some special unit vectors n 1 , . . . , n 5 in R 3 and denote by L ⊂ R 5 the set of all points (L 1 , . . . , L 5 ) ∈ R 5 with the following property: there exists a compact convex polytope P ⊂ R 3 such that the vectors n 1 , . . . , n 5 (and no other vector) are unit outward normals to the faces of P and the perimeter of the face with the outward normal n k is equal to L k for all k = 1, . . . , 5. Our main result reads that L is not a locally-analytic set, i. e., we prove that, for some point (L 1 , . . . , L 5 ) ∈ L, it is not possible to find a neighborhood U ⊂ R 5 and an analytic set A ⊂ R 5 such that L ∩ U = A ∩ U . We interpret this result as an obstacle for finding an existence theorem for a compact convex polytope with prescribed directions and perimeters of the faces. Mathematics Subject Classification (2010): 52B10; 51M20.