Is there a way to edit a topography in AutoCad?

[Anonymous]

I'm trying to edit a very irregular topography that I imported from Sketchup but I can't modify the levels to draw above it like I need to, any advice? 

[TerryDotson]

It looks like (from the picture) that you have a 3dSolid or 3dMesh of a surface (with a flat base and skirt).  You might be able to explode it to work with the surface triangles only.  What do you want to see, contours, cross sections?

[tboehler]

This looks like a Civil 3D model - a 3d view of the TIN lines.  Probably good contours in there if you have Civil 3D.  You can attached the file for us to verify.