Scale to an overlap (s1+s2-d)/s < OMMAX2, keeping s1/s2 ratio. s1 and s2 are the two sphere radii, s is the smallest of these, and d is the distance between the centers of the spheres. The three numbers are for atom-atom, atom-interstitial, and interstitial-interstitial overlap, respectively. The default values are: 0.40, 0.45, and 0.50.