Scale bar or bounding box in volume viewer?

Hi everyone,

I'm really struggling to do a quite straightforward task in my opinion. I have a stack of 2D images that I would like to visualize as a volume, and then just add either a scale bar around the volume or a bounding cube (I'm not sure this is the correct way of saying it) for reference. I tried using volume viewer but its options are not great, and looked through many user-made visualization apps, but without success so far. I'm attaching a picture of what I need to obtain:

anyone faced this issue before? I've tried also in ImageJ, but its volume viewer plugin is really bad in my opinion. Also I don't have the license for Avizo or other expensive softwares. Thank you!