I'm creating this to help spread the word that RNG is indeed possible for Half-Life 2 and I hope that this thread will inspire others to use RNG to make some awesome stuff for this game. A friend of mine Shadow_RUN experimented with Ellie's guides on RNG for L4D2 to see if they would also work in HL2 and turns out it does. The Proof of this working is that a mod of mine (Improved Metrocop Redux V2) now has a RNG VPK. Here are some examples of what we've tried so far.
This method allows the object will use different textures on the same map. For example, one Metrocop has blue yes while the other one doesn't. However, a current issue that we haven't resolved yet is that frame 1 (variant) will turn back to frame 0 (regular) upon death. Basically this (and other forms of RNG) use a section in a VMT called proxies which contain the code of the RNG.
For objects that can't use Real RNG such as static props, this gives an object one randomized texture per map instead of using multiple textures per map. For exmaple, one time loading a map loaded yellow vending machines but whenever I reloaded the map again, the vending machines were red instead. Model RNG This one we're still testing this. Model RNG so far is the most complex to do and to understand. This method gives the impression that a different object is loaded but it is actually using bodygroups. For example, let's say there's a Metrocop with a bodygroup for a different helmet, each metrocop will randomly have the regular or variant helmet.