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The complex eikonal equation in $(3+1)$ dimensions is investigated. It isshown that this equation generates many multi soliton configurations witharbitrary value of the Hopf index. In general, these eikonal hopfions do nothave the toroidal symmetry. For example, a hopfion with topology of the trefoilknot is found. Moreover, we argue that such solitons might be helpful inconstruction of approximated analytical knotted solutions of the Faddeev-Niemimodel.Comment: 31 pages, 21 figures; final version accepted in Eur. Phys. J.

Knotted configurations with arbitrary Hopf index from the eikonal equation