Aha! "-vote" helped immensely. Thanks again!
JLS
> So assuming that anat+tlrc contains the transformation from
> orig
> space to tlrc space for mask+tlrc, then your command might be:
>
> 3dfractionize -template 3d+t+orig -input mask+tlrc \
> -warp anat+tlrc -vote -clip 0.2
>
> That would produce mask+orig, having the same grid as
> 3d+t+orig.
>
> Then you could use programs such as 3dmaskdump or 3dmaskave to
> produce time-series from your mask.
>
> - rick
>