Fix: Unreal Blueprint Set Array Elem Causes Full Replicate

Inventory updates one slot. Network sends the entire 200-slot inventory. Per-mutation cost: 8KB.

Migrate to FastArraySerializer

C++ refactor: derive items from FFastArraySerializerItem; container from FFastArraySerializer. Per-item dirty becomes possible.

MarkItemDirty per mutation

After modifying an item, call MarkItemDirty(Item). Replication sends only that item.

Or batch mutations

If migration is too heavy, batch frequent updates into one per second. Bandwidth cost drops; latency increases.

“Replicated arrays default to full-dirty. Delta replication is an explicit upgrade.”

For any replicated collection over ~10 items, FastArraySerializer is worth the C++ refactor. Bandwidth savings compound over a session.

Related reading

• Fix: Unreal Network Replicate Tarray Resize Spam Bandwidth
• Fix: Unreal Character Movement Replicate Jump Look Mismatch
• Fix: Unreal World Partition Stream Distance Causes Pop In
• Fix: Unreal Substepping Physics Too Aggressive Causes Tunneling