afni.nimh.nih.gov

Sorry about the delay getting back to you regarding this. A mask is not applied with the -1blur_fwhm option for 3dmerge. As you noted from the previous message board posting, the equivalent may be accomplished using the -1fmask and the -1filter_expr options. Bob Cox just changed the default behavior for these options, so you don't have to follow that with another 3dcalc command to apply the mask a second time.

The 3dBlurtoFWHM command does respect a mask, but uses a local smoothing approach.