The -hausd option controls the boundary approximation:
it impose the maximal distance between the piecewise linear representation of the boundary and the reconstructed ideal boundary. Thus, a low Hausdorff parameter leads to refine the high curvature areas.
By default, the Hausdorff value is set to 0.01, which is a suitable value for an object of size 1 in each direction. for smaller (resp. larger) objects, you may need to decrease (resp. increase) the Hausdorff parameter.
Note that you can impose different Hausdorff numbers over different boundary componants using a parameter file.
Example(s): mmg2d_adp1, mmgs_bdy1, mmgs_bdy2, mmg3d_ls1.