So all but one of my custom models are visible and they work perfectly. One (Vendetta model from Garrysmod.org) is invisible in the pointshop. When equipped it works just fine, however when you die the model disappears from the world and falls into an infinite dark void. Body is nowhere to be found. No errors or anything in the console. Is there something wrong with the models physics?
Probbably. Could you show us an image of the physmodel in hlmv?
The model on garrysmod.org is broken. I fixed it here: http://steamcommunity.com/sharedfiles/filedetails/?id=170434323