Hi Jean-Francois, You can save a map with the original map size while using volume zone by first pressing the the "Full" button in the Features / Subregion Selection panel of the volume dialog. Then use the File / Save Map As button. You can see what region will be saved by looking at the Features / Region Bounds panel (and you could type in new bounds there and press the Enter key instead of pressing the Full button). The volume zone capability (Features / Zone) normally uses a smaller box of data so that it is faster. Even when part of the surface is hidden by the zoning the whole surface within the box being used is computed and that is sometimes slow. Tom jean-francois menetret wrote:

Hi Thomas,

when using the zone option in Chimera, is it possible to have the size of the saved mrc file (after zoning) be the same as the original file ?

Best wishes

Jean-Francois