Hello Jeff, really thanks for your reply.
I knew about that button to create a new surface from point clouds but in my case I wish to update a surface previously created, I don't need to create a new surface. So my question is, how can I do that?
Just to be clear I created a surface from "point cloud 1" (I used the "Create surface from point cloud" button you mentioned). I called this surface "Surface 1" and I used it to realize my project.
Now I wish to update "Surface 1" with a "point cloud 2" which I received (I want to overwrite it totally).
I did the following procedure:
1. Attached "point clouds 2" in CIVIL3D
2.Created "Surface 2" from "point could 2"
3. Cancelled objects from "Surface 1" (Surface 1 --> Definition --> Drawing Objects --> Eliminate)
4. Attached "Surface 2" in "Surface 1" (Surface 1 --> Definition --> Edits --> Paste surface --> Surface 2)
5. Cancelled from drawing "Surface 2".
The procedure 1-4 seems to work. However, as far as I cancel "surface 2" points are eliminated also in "surface 1".
Why this happens? Haven't I pasted all information from "Surface 2" into "Surface 1"? How can I eliminate "surface 2" without losing elements also in "surface 1"?
Thanks