It is possible to save the dwg file as an Object which will create a 3D version of the file. Use the Open Object... command, and select Browse for file... at the top of the dialog box. Navigate to and open the dwg file, this will open the file as an Object. Save the file as an Object and then load it into your libraries with the Library Manager. Use the Object Tool to select and place the file, it will appear as 2D and 3D. In 3D it will be flat (all in a single x/y plane).
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
Although this seemed like a legitimate question about how to show a 2D DWG in a 3D view, it was actually a spam post.
The user posts a legitimate question but puts a spam link in their signature.
I have banned the user and so the original post has been deleted.
One of the forum moderators. Versions 6.5 to 25 Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10 Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10