Re: [Chimera-users] calculation of volume

Hi Navnit, Not sure what you mean by "vdw volume". I guess you mean the volume within the vdw surface. That's not just the sum of the spherical atom volumes since those atom spheres overlap, so the calculation is not trivial. Perhaps the following will serve as a useful measure of "compactness". Divide the solvent excluded surface enclosed volume by the solvent excluded surface area. This gives a value with units of distance, a kind of mean radius quantifying the curvature of the surface. For a given volume a sphere will give the largest value, while a shape with many protrusions will give a smaller value. The larger the value the more sphere-like (globular) the shape. Tom