Poliline 2D to poliline

Hello,

i have a file with the topography of a terrain, and i need it to import the dxf file in a program for having my 3d digital terain model. but i have two kind of lines, simple and 2D polylines. How can i convert them all in simple polylines? if it's not possible it's not a must to keep the Z-value(elevation), i can set this manually to each new converted polylines.

here is the file:

http://fbx.ro/d842gw6wivasiwfs

Have you tried the Convertpoly command?

it dosn't do nothing.

You might want to give this a try: http://www.cadtutor.net/forum/showthread.php?t=49122

sorry, but i don't know how to lunch the lisp. i've made a lisp file with the code, i know to load it, but this is the end.

Save the lisp file as Test.lsp, load it in Autocad and then type TEST at the command prompt to run it.