Deliverables for AutoCad

Can someone tell me the file(s) that a client would need for them to produce useable contour lines in AutoCad?

dxf should work for them.

The best AutoCad Civil 3D deliverable would be the surface exported as a .xml. Right now I have found no easy way to accomplish this. This is accomplished with most photogrammetry software such as pixelement, is there some reason this can’t be accomplished with lidar?

Our current process is to take the RockSuveryor ground classified cloud, export it as a 1%, a 30%, and a 95% LAZ and then Tin it in Trimble Realworks then export the sampled cloud and LandXML into C3D. It may need some additional breaklines but otherwise has worked well.
That said, for smaller areas (< ~160 acres) the Tin made directly (the 100%) from the RockSuveryor ground cloud works really well too.

How has the quality of the XML from pixelement been? is it a natural tin or a grid tin?