EF_BONEMERGE
EF_BONEMERGE is defined as 0x001, or 1.
This effect merges this entity's bones of names shared with its parent to the position and direction of its parents.
Usage
In code
Inside of the codebase, effects are defined as a bit-based enum and are stored in m_fEffects. This effect can be manipulated with AddEffects( EF_BONEMERGE ), RemoveEffects( EF_BONEMERGE ), and SetEffects( EF_BONEMERGE ). This effect can be obtained with GetEffects() & EF_BONEMERGE or IsEffectActive( EF_BONEMERGE ).
In scripting
The functions mentioned above are supported in VScript starting with 
Dota 2 . They can also be found in 
Garry's Mod .
In a map
To use this effect in a map, turn off SmartEdit mode and add the following keyvalue pair to the entity: effects 1.
Note:If it is desired to use this with other effects, you should add the integer value of each effect to the value.You can set the effects keyvalue during runtime using AddOutput with the input value effects x (x being any summation of effects flags to enable).
Warning:Using AddOutput to change an entity's effects may interfere with an entity's simulation functionality.