How to generate a deep topographic surface from combined xyz DTM point cloud and cutting planes?

Dear all, I have to generate the depth topography of a sliding mass. I have the point cloud (xyz data set) resulting from the actual topography and I know the orientation of the intersecting planes (4 planes) that define the deep rupture surface. How can I generate a single solid surface formed by the conjunction of the intersecting planes with the topography outside of the sliding source area?

Pascal Golay probably has the best answer. My answer is:
SrfPtGrid command draws a surface from a grid of points that lie on the surface.
CreateSolid command creates a closed polysurface from selected surfaces that bound regions in space. The surfaces must overlap and intersect.

Hi Alberto - can you post a file or send to tech@mcneel.com? It’s hard to picture without the file but I can imagine possibly several intersecting patch surfaces from subsets of the points might work.

-Pascal

Thank you Andrew for your valuable suggestion! I’ll try those commands.

Thank you Pascal for your response! I sent you the file at tech@mcneel.com.