creating .phys to models

I’ve got a .mdl file and i want to create a .phy to it, is there anyway of doing it after the model was compliled to a .mdl?
Just managed to decompile it to .smd’s and .qc.

[editline]15th October 2014[/editline]

ok so I exported it to a .qc and .smd, i tried exporting it again and didn’t get the .phy.
this is my .qc file:

I was wondering how will i be able to re-create a .phy

There’s no collision data being generated because you haven’t told it to do so or given it anything to work with. To do so, you’ll want to use $collisionmodel in your QC which tells the compiler things such as how much the weapon weighs, whether it’s concave, and various other physics-based values. You’ll also need an actual collision mesh which is generally just a very low poly block-like object that will act as a shell around your weapon.

Try decompiling an existing HL2 or CSS weapon and viewing the collision model on top of its reference model to see how it works. That’s generally going be the best way of giving you an idea of how it works.

I didn’t quite get it.
in that link it links it to another .smd file
for example:
$collisionmodel "tree_deciduous_01a_physbox.smd"
$mass 350.0

Yes, that SMD file is the collision mesh I was talking about. Handling collision on a mesh is expensive, so it’s not automatically done from the same mesh. Instead, you make a really low poly shell that covers the mesh, or joints if the model is a ragdoll. Open up the collision model and compare it to the reference model [of the model you decompiled] to see how they handled it. I’d reccomend using a weapon rather than a tree, though.

ok, so if i’ll use another gun’s collison meth it’ll be ok?

I’m not talking about using it directly. You “can” but it’ll most likely result in the gun going through the ground, walls, or other objects in most areas. What I mean is looking at an existing weapon’s collision model to see how it looks and comparing it to the gun it’s made for, then using that knowledge to make your own.