I know that SteamID is used for this, but I want to know if it is possible to find out the appearance of the player by steamID using certain calculations (I know that this can be done using one of the DLCs)
Is there any way to find out what algorithm Rust uses to determine a player's appearance?
There is an administrator command that changes the appearance only from your perspective on that server, but it uses a seed value.
When you create a Steam account and load Rust, isn't a unique fixed seed value assigned?