When I define a static mesh on the spline where I created a long train track, the spline is too slow to be moved anymore.
It works perfectly in UE5.0 but extremely slow in UE5.1.
As the number of points increases, the slowness increases.
Is there some unfamiliar change that slows down the spline in UE5.1?
Thank you
The spline I created in the demo map of the Train template sold in the Unreal Market is too slow to be moved in UE 5.1
I would really appreciate if an Unreal Engine Developer could answer on this.
Because my customers using the product with UE 5.1 have complaints and I haven’t been able to find a solution yet.
At least if this is a BUG that needs to be fixed I can report it to customers
Thank you!
Hi there,
im making a tool that use spline mesh component as well and yes, 5.1 make the spline VERY SLOW, almost impossible to move points.
it work flawless using 5.0 or less.
BTW; check the Add Splne Mesh Component Node inside the blue print editor, turn OFF the collision.
That will make the pline a lot faster (this trick work on 5.0 but it doesnt not work in 5.1). anyway, you can try and maybe it will help a little.
waiting for Unreal response as wel…
Hi @resetme,
Thanks for the reply
Collision is already disabled.
I’ve tried all possibilities and everything else that can be done.
I have minimized the mesh triangle counts.
It was of little use.
The higher the number of points, the harder it is for you to move the spline.
Theres some good news.
is a bug with spline component physics, theres a hotfix for it and you can merge from github already. tha would solve the issue for you, but not for ur costumers, they will need to wait public release 
(or ask them to connect github to unreal, merge the hotfix, compile engine…)
@resetme thanks for this news.
Customers might want to bother to compile it, but it was comforting to learn that this issue will be fixed in the next update.
Hello, can you please point me to the hotfix? Im on the github repo but im not sure what branch/version should i compile… thank you very much
hi there…
do you have access to UDN? is posted there at spline performance 5.1
idk if i can copy paste UDN content 
Hi Resetme,
The github is publicly available, so I don’t see any problem with pointing them to the Fix CL.
nice.
here is the UDN
Spline Mesh performance in 5.1 (unrealengine.com)
CL#22829409.
Unfortunately that only links to the UDN which i can not view
Guess i will have to wait for the 5.1.1 hotfix
The CL is listed on the Github commit, so it made searching the repository for it possible:
https://github.com/EpicGames/UnrealEngine/commit/096d8909ace7f98f42475031d3c71cdd38d05cf1
(You need to log into github and link your account to view)
Hello @Astrotronic, thank you very much. Maybe i dont understand this, but this fix is in the release branch and it was added 28 OCT. Is it not included in the 15 NOV release? I thought the official runtime package was made from this release branch - including this FIX… but im not very advanced so sorry if i dont understand this correctly
No worries, I got a mixed up myself. So, the CL actually is not the fix, but it is the CL that created the problem.
Earlier in this thread:
“it work flawless using 5.0 or less”
So if you needed this functionality ASAP, you’d need to revert the CL/changes. (I’m assuming that since it is being discussed on the UDN the devs are aware and would expect this to be fixed in 5.1.1 or 5.2.)
Thank you. I really hope they will fix this. And there is no mention of the 5.1.1 hotfix anywhere It is so painful to work with my railroad based project now
In 5.1.1 released today, i can verify that this has not been fixed. As any other issues i had with 5.1.
I agree with you.
The first thing I did was test this, unfortunately the same issue still persists.
I guess we have to wait for the 5.2 update.
Yeah can confirm this is still a massive issue in 5.1.
Does we know if 5.2 has a bug tracking this? Or if there is a pull request fixing it?
@Rumzie I’m not seeing it on the issues tracker. But it could be possible that there is a bug in the database but it’s just not public.
The most sure-fire way would be to look at the current code for 5.2 on github and compare it with 5.0/5.1.
Another option, when 5.2 Preview 1 is released, immediately check this, and if it’s still a problem submit a bug report.
Hi,
I would like to provide a feedback on the bug report form.
I tried to fill out this form, but since my English is not enough, I had a little difficulty and frankly I could not succeed.
Because almost all form fields are required to be filled. This problem was actually a problem that could be explained in one sentence.
It would seem like it would be better if they had a simpler bug report form so we could submit more obvious issues like this.
Or, at least, the obligation to fill in all form options can be reduced.
Thank you.