The QC command
$origin adjusts the position (and optionally Z rotation) of a model within its own local space. During compiling, it will be offset by the X, Y, -Z and Z-rotation values provided.
This is useful when adjusting view models, for ensuring that models don't spawn inside the world, and helping in the arranging of clusters of separate models that need to be aligned precisely with each other (e.g. parts of a building).
$origin <x> <y> <-z> [z rotation]
Note that Z's value is reversed.