My mod adds abilities. These abilities range from spawning entities, spawning blocks, to changing the player's renderer and such. I am not sure how to implement it for multi-player.

I believe I can send a packet from the client to the server indicating that the ability has been executed, the server checks if the player can use the ability (to prevent cheating), and then sends that same packet to the other players that are in range (?). 

 

What do you think? Is this the optimal way to do it?

6 hours ago, diesieben07 said:

How is the ability activated?

The player uses a keybind+click to activate an ability.

23 minutes ago, diesieben07 said:

Okay then you'll have to send a packet to the server when this is done. This is the case in both singleplayer and multiplayer. The two are fundamentally the same thing, both use a server and a client. You shouldn't treat them any different, it only leads to bugs.

This answer does not help me. 

Is sending a packet to the server, then the server sending a packet to all the other clients ultimately the best way of doing it? Would it complicate rendering effects on other players? Has it been done before? How do I know which players to send the packet to (other players which can see the player executing the ability)?

1 hour ago, diesieben07 said:

Yes that is the way to go.

To send a packet to all tracking players you can use PacketDistributor.TRACKING_ENTITY or TRACKING_ENTITY_AND_SELF to also include the player themselves.

Not sure why it would complicate rendering. It is the only way to do it.

What happens if a player e.g teleports to another player which is using an ability? wouldn't that break the system?