Function scale_bem

mne/coreg.py:894–946

Scale a bem file. Parameters ---------- subject_to : str Name of the scaled MRI subject (the destination mri subject). bem_name : str Name of the bem file. For example, to scale ``fsaverage-inner_skull-bem.fif``, the bem_name would be "inner_skull-bem

(
    subject_to,
    bem_name,
    subject_from=None,
    scale=None,
    subjects_dir=None,
    *,
    on_defects="raise",
    verbose=None,
)

@verbose
def scale_bem(
    subject_to,
    bem_name,
    subject_from=None,
    scale=None,
    subjects_dir=None,
    *,
    on_defects="raise",
    verbose=None,
):
    """Scale a bem file.

    Parameters
    ----------
    subject_to : str
        Name of the scaled MRI subject (the destination mri subject).
    bem_name : str
        Name of the bem file. For example, to scale
        ``fsaverage-inner_skull-bem.fif``, the bem_name would be
        "inner_skull-bem".
    subject_from : None | str
        The subject from which to read the source space. If None, subject_from
        is read from subject_to's config file.
    scale : None | float | array, shape = (3,)
        Scaling factor. Has to be specified if subjects_from is specified,
        otherwise it is read from subject_to's config file.
    subjects_dir : None | str
        Override the SUBJECTS_DIR environment variable.
    %(on_defects)s

        .. versionadded:: 1.0
    %(verbose)s
    """
    subjects_dir, subject_from, scale, uniform = _scale_params(
        subject_to, subject_from, scale, subjects_dir
    )

    src = bem_fname.format(
        subjects_dir=subjects_dir, subject=subject_from, name=bem_name
    )
    dst = bem_fname.format(subjects_dir=subjects_dir, subject=subject_to, name=bem_name)

    if os.path.exists(dst):
        raise OSError(f"File already exists: {dst}")

    surfs = read_bem_surfaces(src, on_defects=on_defects)
    for surf in surfs:
        surf["rr"] *= scale
        if not uniform:
            assert len(surf["nn"]) > 0
            surf["nn"] /= scale
            _normalize_vectors(surf["nn"])
    write_bem_surfaces(dst, surfs)


@verbose