Advice on comparing two smooth surface

[carter7gindenv]

Hello, I'm trying to merge two laser scans together (very flat rock plates). Both have part of the other one in their cloud. Problem is the surfaces are a bit too smooth and CC doesn't merge them correctly.
What I have done already was roughly align them to where they should overlap and then proceed to finely register them.

I'm thinking about making "marks" on the plates (for "align by picking point") to help CC align them but I wanted to know if there was anything else I could try in CC to be more accurate?

The final goal would be to do a before/after comparison.

Thanks for the help!

[daniel]

If they are super smooth / flat, then indeed the ICP algorithm can't work. And your idea of adding marks is probably the best solution!