Because they are proprietary, you won't find them on standard open-source repositories. To get legitimate, high-quality models, you should head to the following official sources:
The file may have been uploaded as ASCII but saved as binary. Open it in Notepad++ – if you see readable text (like MAP_DATA 512 512 ), it’s ASCII. Rename to .txt , then back to .v3m after cleaning line breaks. v3m files download
: Another official source for purchasing professional-grade 3D reliefs in the V3M format. The Ultimate Guide to V3M Files Download: Everything
Which are you currently using (VCarve, Aspire, Fusion 360, etc.)? it’s ASCII. Rename to .txt