You need a tool capable of reading the Source Engine's proprietary model system.
Since VTX files are compiled for game performance, you cannot "open" them directly in most software. You must first them back into a source format (like SMD) and then export to FBX. 1. Decompile the Source Files vtx to fbx
: This is the industry-standard decompiler for Source Engine models. It can process the combination of .mdl , .vtx , and .vvd files into SMD (Studio Model Data) files. You need a tool capable of reading the