EF_NODRAW
EF_NODRAW prevents any data about an entity from being transmitted to the client, without affecting it on the server. In other words, it makes the entity disappear from the player's view without deleting it.
It is defined as 0x020, or 32.
Note:Since the client doesn't draw entities with this at all, collisions may be strange in multiplayer games.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_NODRAW ), RemoveEffects( EF_NODRAW ), and SetEffects( EF_NODRAW ). This effect can be obtained with GetEffects() & EF_NODRAW or IsEffectActive( EF_NODRAW ).
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
Starting with 
Portal 2, this effect can be toggled via the Enable/DisableDraw inputs.
In earlier titles, you must turn off SmartEdit mode and add the following keyvalue pair to the entity: effects 32.
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.