Hello from @lastools, please use the URL http://lastools.org/ to refer to LAStools from now on. To turn ASCII to LAS or SHP you can use txt2las.exe or las2shp.exe. But all LAStools can directly read TXT or SHP files via on-the-fly conversion to LAS. In terms of point classification I do not think that ArcGIS 10.1 will have the full functionality you need. The most crucial task is that of ground / building / vegetation classification. Here you need to look at lasground.exe or lasheight.exe or lasclassify.exe. Or have a look at the other tools that Andrew mentioned. Cheers, Martin @lastools
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