12d Model

The top of the file in Notepad looks like shown below. I believe it may be an xyz file. Problem being it is from a LIDAR survey and is huge, exceeds 5M points. The surveyor does not seem to be able to make it smaller. Will keep trying. Thanks. " 0 1 1 9 0 0.000000000000000 0.000000000000000 0.9...

I am trying to input a .DEM file from a surveyor but get an error message "cell size not defined". There no option to set cell size. Any suggestions.