How do I set up my HFMV?

First of all.
What program are you using to view hl2/gmod models in?

I’ve tried with Source SDK’s modelviewer which I can’t to work. I have also tried a few others which crashes upon start >.<…

Btw. what decompiler are you guys using? Mine crashes every time I try to decompile a model too x.x

I’m guessing you meant HLMV (Half-Life Modelviewer)? I personally compile models using Source Sdk Base 2013 to the SFM directory and use SFM’s modelviewer, then just transfer models over to GMod for testing. Source SDK is currently broken and has been since 2012. It most likely won’t be fixed. Tools in certain games work here and there, but I know for sure SFM’s tools and Source SDK Base 2013’s tools work.

As far as decompiling, I wouldn’t reccomend decompiling unless you have to, but Crowbar is the optimal choice these days. I’d reccomend building a new QC though.