Hi Rutvik,
A maximum absolute value function seemed like a good idea,
and as long as I was at it... :)
3dVol2Surf now has the options '-oob_index INDEX' and
'-oob_value VALUE'. It also has the mapping function
max_abs, which will output the value with the greatest
absolute value (note that it does not output the absolute
value, the original sign is preserved).
This will be available in the next update of AFNI. If you
are interested in having the program earlier, I can give
you the source file.
Thanks,
- rick