# \[Critical\] Extreme lag / performance problems on UEFN islands with creatures & wildlife while building enabled **URL:** \ **Category:** Issues and Bug Reporting\ **Tags:** fortnite-creative, unreal-editor-for-fortnite, fortnite\ **Created:** [January 3, 2024, 6:00pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206 "2024-01-03T18:00:49Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [January 3, 2024, 6:00pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/1 "2024-01-03T18:00:49Z")
### Reference ID 0bd51358-41fd-1e9b-633d-539073794ca1 ### Please select what you are reporting on: Creative ### What Type of Bug are you experiencing? Assets ### Summary This is a very critical issue for big open-world maps that rely on creatures and buildings as a gameplay element as it will cause players to leave much earlier due to the performance impact!! On a big island with creatures/wildlife spawning recently, the server has huge performance problems. This worked perfectly before and only recently started to reappear. I think this has been patched before and might have been reintroduced accidentally with one of the latest Fortnite updates. My best guess would be that this has to do with the navmesh for aI pathing being altered by placing builds by a player. When a player places a build the game hangs for a small amount of time. In my open-world map ForestZ I had a perfectly working build. When updating this error occurred there as well. On a different open-world map I made this error occurred already from the start. Playing the private build of that version of ForestZ that was working also has these issues and all the new private/public builds have it as well I have tested removing creatures/wildlife and it 100% solves the performance issues so this is the cause! ### Steps to Reproduce Make a big map with complex landscapes and obstacles (trees, buildings, etc). Add creatures and wildlife and enable the building Start the game, wait for creatures to spawn (Already laggy), and then place builds. You will notice a big delay/lag spike ### Expected Result No lag as this has already worked without any performance issues before!! ### Observed Result Extreme server lag spikes ### Platform(s) windows ### Island Code 3422-8734-7108 ---
**Author:** ![Bug-Reporter](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/bug-reporter/32/997076_2.png) [@Bug-Reporter](https://forums.unrealengine.com/u/Bug-Reporter)\ **Post date:** [January 3, 2024, 7:18pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/2 "2024-01-03T19:18:30Z")
The status of UCB-1152 incident has been moved from ‘Closed’ to ‘Needs Triage’. ---
**Author:** ![crawrs](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@crawrs](https://forums.unrealengine.com/u/crawrs)\ **Post date:** [January 17, 2024, 8:43am UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/3 "2024-01-17T08:43:44Z")
Would like this to be reopened - Guard spawners, wildlife, etc, simply lag SO bad! Causes rubber banding while doing anything. ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [January 22, 2024, 3:01pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/4 "2024-01-22T15:01:40Z")
This definietly still happens. Just tested it out on my map ForestZ. - Enabled building in UEFN settings. - Wait for zombies to spawn - Build - Extreme lag spike / rubberbanding ---
**Author:** ![Senix](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/senix/32/705104_2.png) [@Senix](https://forums.unrealengine.com/u/Senix)\ **Post date:** [January 22, 2024, 3:29pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/5 "2024-01-22T15:29:08Z")
This has something to do with the “Can affect Navigation” and “Nav Mesh Flag” setting in the placed meshes. ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [January 22, 2024, 5:14pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/6 "2024-01-22T17:14:16Z")
Yeah its probably the recalculation of nav meshes on the fly. Sadly if a player places fortnite builds while playing this always affects navigation so this is probably what is causing it ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 11:31am UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/7 "2024-02-01T11:31:30Z")
Issue Still persists. Here is a video of it. > Another one with the path being updated and rubberbanding: > Removing the creatures eliminates 100% of the lag. It feels like the updating of the navmesh of the island is causing the server to lag (Maybe the nav mesh is updated in the main thread of the server instead of asynchronously / parallel which causes the problems) Please reopen! Also if anyone has found a workaround for this other than disabling the building completely please drop it in here as this decreased my average playtime by 5 minutes and had already been fixed in a previous version of Fortnite 🙂 ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 12:44pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/8 "2024-02-01T12:44:43Z")
Little update on this topic: The rubberbanding also occurs on a newly created project with a new flat landscape and default material and a bunch of creature / wildlife spawners placed when building a few wooden ramps while the game is started. When replacing the landscape with a world grid cube it does not cause rubberbanding so the lanndscape is definietly involved in this. Updated Easier steps to reproduce: - Create new blank project - Create new landscape with jungle chapter 4 material - Place a bunch of creature and wildlife spawnners with default settings - Start game and build a few wooden ramps near the creatures =\> Rubberbanding occours Will investigate into this further ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 12:53pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/9 "2024-02-01T12:53:10Z")
Update 2: After removing the world grid cube and placing down another landscape it works without lag. It def has something todo with the landscape. Investigating further 😉 ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 1:07pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/10 "2024-02-01T13:07:33Z")
Update 3: New project did the same - same result. STill rubberbanding But when placing a ramp in edit mode and starting the game with the ramp still beiing there it did not rubberband. I have the suspicion this occours only on worlds that do not use any props / bulidings on the on the normal fortnite grid and only use build to prop. My current suspicion is if you do not have at least 1 structure on the structural grid it will create it at runtime causing huge lag ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 1:21pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/11 "2024-02-01T13:21:43Z")
Update 4: Tested back on my main project building a ramp in edit mode and starting the game then building (So the suspicion for the cause has to be wrong) =\> no success , still rubberbanding ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 1:43pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/12 "2024-02-01T13:43:36Z")
Update 5: After testing removing the landscape from my main project it still did not fix the rubberbanding when building. Only removing creatures so far has removed the rubberbanding. I also tried removing all verse devices which changed nothing and will now go on removing all devices type by type as well as props Video: Removed all landscape, all verse device, many props and device but it is still happening ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 2:30pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/13 "2024-02-01T14:30:33Z")
Update 6: After deleting nearly everything besides the default world grid cube floor and 5 creature spawners the rubberbanding goes away =\> Conclusion: when either removing most of the map the lag goes away of leaving all of the map and only removing creature spawners / wildlife it is clearly the creature / wildlife spawners that is the cause in combination with props, landscape and other devices ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 1, 2024, 2:53pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/14 "2024-02-01T14:53:50Z")
If anyone finds a solution or has more info on this please post in here too ---
**Author:** ![PUZZLER](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/puzzler/32/1157972_2.png) [@PUZZLER](https://forums.unrealengine.com/u/PUZZLER)\ **Post date:** [February 6, 2024, 9:42pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/15 "2024-02-06T21:42:00Z")
This is the same bug that has been around for months now that occurs when any animations play such as from sequencers, airdrops, mantling, prop movers, vehicles. I assume its the same with building as there are animations playing (networked ones). Unable to make maps with creatures for a few months because of this. @Flak ---
**Author:** ![Flak](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/flak/32/769441_2.png) [@Flak](https://forums.unrealengine.com/u/Flak)\ **Post date:** [February 7, 2024, 11:12am UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/16 "2024-02-07T11:12:55Z")
Thanks for the ping, we’ll get someone to take a look. ---
**Author:** ![Flak](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/flak/32/769441_2.png) [@Flak](https://forums.unrealengine.com/u/Flak)\ **Post date:** [February 7, 2024, 1:06pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/17 "2024-02-07T13:06:19Z")
@chrisp_games Do you have World Partition on? Could you DM me your logs? ---
**Author:** ![chrisp\_games](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chrisp_games/32/895155_2.png) [@chrisp\_games](https://forums.unrealengine.com/u/chrisp_games)\ **Post date:** [February 20, 2024, 11:44am UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/18 "2024-02-20T11:44:36Z")
Yes world partitition is enabled 🙂 Will send you the logs as DM Also just tested and still happening as of 28.20. Logs do not seem to have any indicator that could cause the bug. I am still pretty sure the lag / rubberbaning is caused by AI Navmesh creation / adjustment. As the player is building the AI has to check for a new path , the navmesh changes which causes the stutter / rubberbanding ---
**Author:** ![Flak](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/flak/32/769441_2.png) [@Flak](https://forums.unrealengine.com/u/Flak)\ **Post date:** [February 20, 2024, 2:55pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/19 "2024-02-20T14:55:55Z")
Thank you, it doesn’t look like I’ve received your logs, could you try to send again? ---
**Author:** ![TKXXXX](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@TKXXXX](https://forums.unrealengine.com/u/TKXXXX)\ **Post date:** [March 29, 2024, 11:49pm UTC](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206/20 "2024-03-29T23:49:35Z")
The lag is more obvious in Private/Publish version than Launch session’s. When I wait like 5-10min. after starting the game, I can build normally though. [Next page](https://forums.unrealengine.com/t/critical-extreme-lag-performance-problems-on-uefn-islands-with-creatures-wildlife-while-building-enabled/1585206.md?page=2)