where to download for free dem data for creating countour in 3d analys
@thales007 has already provided an answer but you might want to tell us more specifics about your geographic location of interest. USGS dem at 90m resolution is available for the entire globe but 30m resolution is only available for the the US. Different countries, states and municipalities may offer dem frre of charge (In my province of Ontario, Canada 10 and 20m resolution dem is available free of charge, in Prince Edward Island, Canada LiDAR coverage of the entire province is available, but other provinces do not offer high resolution dem free-of-charge). I think your question is beyond the scope of these (ESRI) forums. You might have better luck at the GIS Stack Exchange forums or other more generic GIS discussion forums.
