The CIF file was originally designed to transmit crystallographic structure information. The mmCIF file is a variant which transmits data on macromolecules using atomic coordinates on Cartesian axes, not fractional coordinates on crystallographic axes. In this form, the data are not usable by CRYSCON.
However mmCIF files usually have the information necessary to transform the coordinates back to crystallographic axes. The Cartesian-to-crystal transformation matrix is in lines of the type
_atom_sites.fract_transf_matrix[1][1] 0.023496
which make up a 3 x 3 transformation matrix, plus translations. The parameters may or may not be in a "_loop".
This is the inverse of the required matrix for CRYSCON. If the axes are orthogonal (orthorhombic, tetragonal, cubic systems), the off-diagonal elements are zero and the diagonal elements of the required matrix are simply the original crystallographic axis lengths themselves, which are given in lines like
_cell.length_a 42.560
The coefficients of the inverted matrix may be entered directly into the Transformation Parameters dialog. The transformation should be on "Input atoms only", otherwise CRYSCON will reject the original generated atoms as not being in the unit cell. The result will be a set of atoms for a complete molecule, with atomic coordinates on the crystallographic axes. Some of these atoms may be redundant in the original crystal symmetry, which may be given in the mmCIF file in lines like
_symmetry.space_group_name_H-M 'P 43 21 2'
If there is sufficient interest in using mmCIF in crystallographic (not molecular) form, the capability to transform automatically can be added to CRYSCON.