$bodygroup
$bodygroup is a QC command that defines a group of meshes that can be turned on or off, or changed entirely. Server code can change their state.
Note:Body groups cannot change skeletons or collision models.Example
This body group allows a weapon to have iron sights, laser sights, or no sights at all:
$bodygroup sights
{
studio ironsights
studio laser_dot
blank
}
This body group defines the entire chest region of the model, which spans multiple bones:
$bodygroup chest
{
studio chest_with_no_armor
studio chest_with_light_armor
studio chest_with_heavy_armor
studio chest_with_super_armor
}
Note:Since body group polygons never share vertices with the base mesh in Source models, there need not be seams between properly-made components.Bodygroups in Level of Detail Meshes
Using Level of Detail meshes - especially for high-poly geometry - is highly recommended. Body groups can be used in $lod strings in the same method as normal geometry meshes:
$lod 12
{
replacemodel chest_with_no_armor chest_with_no_armor_lod1
replacemodel chest_with_light_armor chest_with_light_armor_lod1
replacemodel chest_with_heavy_armor chest_with_heavy_armor_lod1
replacemodel chest_with_super_armor chest_with_super_armor_lod1
}
$lod 18
{
replacemodel chest_with_no_armor chest_with_no_armor_lod2
replacemodel chest_with_light_armor chest_with_light_armor_lod2
replacemodel chest_with_heavy_armor chest_with_heavy_armor_lod2
replacemodel chest_with_super_armor chest_with_super_armor_lod2
}
$shadowlod
{
replacemodel chest_with_no_armor chest_with_no_armor_lod2
replacemodel chest_with_light_armor chest_with_light_armor_lod2
replacemodel chest_with_heavy_armor chest_with_heavy_armor_lod2
replacemodel chest_with_super_armor chest_with_super_armor_lod2
}
Programming
To change a body group's state:
static int BodyGroup_Sights = FindBodygroupByName("sights"); // calculate this value once
SetBodygroup( BodyGroup_Sights , 1 ); // laser dot
By default, CBaseAnimating supports 4,294,967,296 combinations (32 bits), and CBaseViewModel supports 256 (8 bits). You can raise either of these by editing the relevant SendProp for m_nBody.
To calculate how many combinations you need, multiply the size of all your bodygroups together. The examples on this page total 3 * 4 = 12...but add two more groups the same size and you're up at 144. The figure grows exponentially.
Swithing bodygroup via $Sequence
It is possible to swap bodygroups during sequences, using the following event:
AE_CL_BODYGROUP_SET_VALUE <frame> "<bodygroup name> <body>"
Note:So far only tested in 
. Seems to be buggy and unreliable.Example:
$bodygroup "travel"
{
studio "delorean_Notravel.smd"
studio "Delorean_Yestravel.smd"
blank
}
$sequence "charger_escape_b" {
"racecar_anims\charger_escape_b.smd"
{ event AE_CL_BODYGROUP_SET_VALUE 0 "travel 0" } // On frame 0 Sets model to show body 0 (first variant) of the "Travel" Bodygroup. Being "delorean_Notravel.smd"
{ event AE_CL_BODYGROUP_SET_VALUE 50 "travel 1" } // On frame 50 Sets model to show body 1 of the same bodygroup. Being "Delorean_Yestravel.smd"
{ event AE_CL_BODYGROUP_SET_VALUE 220 "travel 2" } // On frame 220 Sets model to show body 2 of the same bodygroup. Being "Nothing"
}
The above example has been taken from this Jimmy Gibbs racecar mod. Howe