Hi Jeff, The volume dialog "zone" feature does not work with solid (volumetric) rendering. The current implementation just hides surface triangles having vertices outside the given range so it only works on surfaces. When you use volume dialog File / Save map as... it makes a copy of the data with grid values set to zero outside the radius. Creating a copy of the map in memory or masking the map for use with solid rendering are not currently supported. We wish to add this in the future and it should not be hard to achieve although performance when changing the radius will be significantly worse than with the current surface zoning. The documentation does not mention this limitation and I will update the volume dialog description to describe it. Tom Jeff wrote:

hi Tom,

is there a way to get the zone tool to operate when doing a solid/volume rendering - in surface mode, if you set a zone radius, let's say 40 A, you'll get a region that extends 40 A around the selected marker(s); however, in 'solid' mode, it appears I get the entire orthogonal region in the volume that encloses the markers plus that radius. thiis is problematic if the markers span the hypotenuse of the volume; in that case, zone with volume/'solid' appears to more or less display the entire volume rather than just the surrounding region as in 'surface mode'

do I have a buggy version? this is a recent release, but I've had this happen with previous releases

-jeff