We present a new realisability model based on orthogonality for Linear Logic in the context of nets-untyped proof structures with generalized axiom. We show that it adequately models second order multiplicative linear logic. As usual, not all realizers are representations of a proof, but we identify specific types (sets of nets closed under bi-othogonality) that capture exactly the proofs of a given sequent thus proving a completeness theorem. Furthermore these types are orthogonal's of finite sets; this ensures the existence of a correctnesss criterion that runs in finite time.