Method for parallel approximation of distance maps on a discrete representation of a manifold, the method comprising: for at least one Euclidean grid applied on the discrete representation of a manifold, iterating over rows of the Euclidean grid in a first direction, and for each row currently visited during the iterating in the first direction, calculating a distance value for each single cell of the currently visited row in parallel, wherein the calculating is carried out according to a predefined approximation rule, using a distance value calculated for each one of respective cells of a row visited immediately before the currently visited row, wherein the cells of the row visited before the currently visited row are adjacent to the single cell in the Euclidean grid.