I have preprocessed a set of resting state images using AFNI ver 21.2.04 (‘Nerva’). The anatomical images were sent through SSwarper and recon-all and my proc.py script was modeled after example 11. I am using a functional atlas that consists of 90 ROIs in MNI space. I was hoping to calculate some QC-FC metrics as described in Ciric et al (2017) to evaluate the distance-dependent effects of motion on functional connectivity before and after denoising. To do this, a distance matrix is created by calculating the euclidean distance between the centers of mass of all node pairs. Using the 3dCM command I was able to extract the center of mass of each ROI. For calculation of the euclidean distance, I see the SurfDist command, however, my data is volumetric rather than surface-based. Is there any other function in AFNI that can be used to calculate euclidean distance between each ROI pair center of mass in volumetric space?