There was a download of TopoGX 1.551 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The software belongs to Photo & Graphics Tools.
The following version: 1.5 is the most frequently downloaded one by the program users. You can run this PC program on Windows XP/7/8/10/11 32-bit. TopoGX.exe is the default file name to indicate this program's installer. This software was originally designed by SoftSoft Ltd.
From the developer:
TopoGX is a high quality software application which can intelligently convert a 2D DXF drawing into a useful 3D DXF drawing. It is intended for surveyor produced drawings like the one to the right here, but is equally suited to any 2D drawing where the Z levels are represented as text items.
You may want to check out more software, such as DwgConverter, which might be similar to TopoGX.