Freeware - Autocad and DWG viewers

Here they are some free autocad viewers:
  1. On line viewer:
  2. DrawSighth 2018

  3. Autodesk DWG TrueView 2018

[Update 2019.10.23]

This is new Drawsight version link, be aware that old free software is no longer working on 31/12/2019. New versions are no longer for free.

[update 2020.04.29]

I am adding another free autocad viewer.

It is not user frienly but, in some cases, it could be useful: