$illumposition
$illumposition is a QC command available in all 
Source games. It sets the lighting origin for the model, relative to its origin. By default the $illumposition is the model's origin.
When illuminating an animated or moving model in the engine, the lighting calculations are only done for the two brightest light sources, via the worldlights lump. All the other lights, as well as bounced light from the environment, are taken from a single ambient cube.
You can optionally specify a bone name for the illum position. If you do, the position specified will be interpreted as being relative to the specified bone.
Note:$illumposition can be overridden per-entity on most entities (including prop_static) by using the lightingorigin KV.Syntax
$illumposition (x) (y) (z) [optional bone name]
Examples
$illumposition 0.000 0.048 -0.115
$illumposition 0.000 9.21 4.00 ValveBiped.Bip01_Pelvis
