How to mark the position of fracture in a 3D model

Dear Everyone,

My app involves recovering fractured eye orbit. The original fractured one is like this :

And the recovered one (with holes-filled) will be like this :

To facilitate post processing, I need to mark down the original fractured position on the recovered image like this :

I wonder if I can do this by just overlapping the fractured image with the recovered one, each with a different colors, so that the fractured position can be depicted. There are 2 similar functions imadd() and imfuse() but I am not sure which one I should use.

Grateful if anyone can help.

Thanks,

Ringo