DWG file for 3D house planning - looking for software

You can register with Autodesk and use the free online viewer. To my knowledge, there is currently no free viewer for Mac. There is one for iPhone or iPad Pro.

Try DraftSight. In my opinion, the program is the best free alternative to AutoCAD. It is also structured like AutoCAD. I drew my electrical installation plans with it. I believe it is provided by the makers of SolidWorks (competitors to Autodesk AutoCAD). If the DWG file contains 3D information, you can also load it with DraftSight.

Please do not get a complicated AutoCAD trial version. That is not necessary with DraftSight.

Well, I don't find DraftSight free..?

Oh damn. Now they have apparently changed it. It seems to be free only until the end of the year. Download the 30-day version (see link in PN). After the 30 days expire, I can always extend it for another 30 days by providing my email address. I've been using the program for free for 5 years now.

You don't have 100 posts yet. PM is not possible. Google for DraftSight 30-day license.

That also probably won't work anymore from 31.12.2019 (according to their website). So SweetHome3D remains the only option :-/

So:
1. Convert DWG to OBJ (Architect, test version of other software, possibly Blender)
2. Import OBJ into SweetHome3D
3. Live with SH3D...