NPCs/NpcbodyGroupRandom.cs
using Sandbox;

public sealed class NpcbodyGroupRandom : Component
{
	[Property]private SkinnedModelRenderer SkinnedModelRenderer { get; set; }

	protected override void OnAwake()
	{
		base.OnAwake();

		if (SkinnedModelRenderer != null)
		{
			if ( Game.Random.Int( 0, 1 ) == 1 )
			{
				SkinnedModelRenderer.SetBodyGroup( 0, 1 );
				SkinnedModelRenderer.SetBodyGroup( 3, 2 );
			}
			else
			{
				SkinnedModelRenderer.SetBodyGroup( 0, 0 );
				SkinnedModelRenderer.SetBodyGroup( 3, 3 );
			}

			SkinnedModelRenderer.SetBodyGroup(1, Game.Random.Int(0, 2));
		}
	}
	protected override void OnUpdate()
	{

	}
}