Because software distribution changes frequently, it is vital to download from trusted sources. As of 2021 (and subsequent years), here is the safe method:
The is a specialized, high-performance visualization tool designed by the ISD Group to enable users to view, measure, and analyze complex 2D and 3D CAD data without needing a full HiCAD license. hicad viewer 2021
Unlike generic DWG/DXF viewers, the 2021 version of the HICAD Viewer focuses on: Because software distribution changes frequently