afni.nimh.nih.gov

Dear Afni experts:

I use 3dAllineate to register
imgA to imgB and get the regImg1 and reg1.aff12.1D
then
regImg1 to imgC and get regImg2 and reg2.aff12.1D

Now I would like to concatenate the transformation matrix using cat_matvec.
Should the order of the input matrix be:
reg1.aff12.1D reg2.aff12.1D
or
reg2.aff12.1D reg1.aff12.1D

Thanks in advance !!

Yiyu