[Mossie]

Great, got the points in, but unable to create surfaces as suggested.

I get message "Unable to perform this function becuase one or mare points are in the same position or plane" I tried surfaces using all three options, but the same message.

Then tried just selecting 4 vertices, same message.

There are 40804 vertices, spaced at 50 meter intervals, representing 10 km square.

Maybe too much data ? Or as it is a terrain model, a number of points are at sea level and thus 0 altitude.