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Need Help With Projectile Lag

Hey Guys, I really need some help.

We just got to stress testing our game when…we came across this horrible mess:

The Projectile Spawn Lag.

When we use a packet lag of over 100ms we get the projectile spawning way off the spawn point. I have read many many posts about how to resolve this however many of them are old an no longer have the BP refence, make no sense at all, or are a partial dead end.

Video showing whats happening:

We use high speed vehicles in our game, and resolving this issue is critical before we can release it. Does anyone have a reference to a tut or post that explains the workaround for this??

If none exist, and anyone has even an idea of how to resolve this, please let me know.
I have tried spawning the projectile on the client and it works fine, but as soon as i spawn from the server and replicate, i get this horrible spawn lag. I can almost get it working but either i get an extra projectile spawning (as a result of replication) on the client, OR i cannot see the projectile spawning on the server on the client.

It seems that everything I try leads to a partial dead end. I cant image the solution for this requires a complete hack to fix.

I haven’t seen any “worthwhile” tutorials for lag compensation. Especially for projectile based shooters.

The big hitch in BP is the “replicate to all but owner” wall. In C++ you can use Conditional Property Replication. Specifically the “COND_SkipOwner” flag.

I’ll be getting back to refactoring my approach in a few days. Eventually I want to release it to the community (free).


Eventually you will need to look into mitigating high ping advantage/disadvantage. The issue with HP’s is replication delay which results in hits behind cover and other BS that degrades the experience of other players… “BLEEPING HITREG”. For shooting HP’s it’s missing hits because of the delay.

Eventually you will need a Frame History Time (FHT) buffer to run sims against for shooters with high pings.

You will also more than likely need a separate FHT for fast moving vehicles.

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