If you are trying to from a file you cannot open, I can guide you on: Finding a free trial for compatible software. Converting .art to .stl or other open formats. Troubleshooting missing fonts that make text unreadable. How would you like to proceed with your file ? Adding Text to a 3D Model in ArtCAM Express (2015)
I can then provide specific conversion steps or software recommendations. Share public link artcam file viewer
Vectric software is the main competitor to ArtCAM and features robust import filters. If you are trying to from a file
There is no perfect, free, modern "double-click" viewer for ArtCAM files. Your best bet depends on your budget: artcam file viewer