Pad ROI image to reference image

[Carl]

Greetings,

I am looking for a tool to pad a ROI image to a reference image. Basically to make the two volumes share the same size. I have tried c3d "match bounding box", but the image is stretched out, but I am looking for a tool to only pad with zeros on the ROI volume so that they match. Is there such a feature in c3d?

-Carl