# Severe spline mesh bug (Demo project included) **URL:** \ **Category:** World Creation\ **Tags:** bug, unreal-engine, Spline, question\ **Created:** [April 19, 2017, 3:56am UTC](https://forums.unrealengine.com/t/severe-spline-mesh-bug-demo-project-included/391269 "2017-04-19T03:56:08Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Slavq](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Slavq](https://forums.unrealengine.com/u/Slavq)\ **Post date:** [April 19, 2017, 3:56am UTC](https://forums.unrealengine.com/t/severe-spline-mesh-bug-demo-project-included/391269/1 "2017-04-19T03:56:08Z")
Simple to reproduce, just add a couple of spline meshes along spline - they’ll behave like that: 134732- However, when using a mesh that is a cylinder without any loop cuts, it works properly: 134733- Also, changing the mesh count to lower value (but too low to be smooth looking) causes the bug to disappear. I’ve included all of this in the simple demo repro project: [DEMO REPRO PROJECT][3] I’d be great if we could even use some workaround for this bug for now… But can’t find any. Thank you! ---
**Author:** ![TJ\_V](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/tj_v/32/1008648_2.png) [@TJ\_V](https://forums.unrealengine.com/u/TJ_V)\ **Post date:** [April 25, 2017, 6:13pm UTC](https://forums.unrealengine.com/t/severe-spline-mesh-bug-demo-project-included/391269/2 "2017-04-25T18:13:39Z")
Hi Slavq, I don’t believe what you are seeing is a bug. For every mesh you add for ‘resolution’ you would need to interpolate another spline point inbetween the other points. I’m going to move this over to the blueprint section for now and one of the other techs has setup something similar to this in the past. He is going to take a look as soon as he has time. Also, in your demo project; both the ‘with’ and ‘without cuts’ meshes had the segmenting error for me. Did you just swap the mesh or did you also change a value somewhere? ---
**Author:** ![Slavq](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Slavq](https://forums.unrealengine.com/u/Slavq)\ **Post date:** [April 25, 2017, 6:27pm UTC](https://forums.unrealengine.com/t/severe-spline-mesh-bug-demo-project-included/391269/3 "2017-04-25T18:27:27Z")
Thank you. Yes, just swapping the mesh, that’s why I thought that it’s a bug. Here is a gif that demonstrates this: ![](https://d3kjluh73b9h9o.cloudfront.net/original/3X/8/0/80d1935593c9ab06e3a29153487f401a767f2d25.gif) ---
**Author:** ![anonymous\_user\_0c62419a](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_0c62419a](https://forums.unrealengine.com/u/anonymous_user_0c62419a)\ **Post date:** [April 25, 2017, 9:24pm UTC](https://forums.unrealengine.com/t/severe-spline-mesh-bug-demo-project-included/391269/4 "2017-04-25T21:24:27Z")
Hey Slavq, I took a look at your project and after investigating I don’t think you are doing anything wrong. The math is correct and the workflow seems correct. What is happening is the vertices between the start and end point of the mesh aren’t scaling in a way that is proportionate to the end points. That creates bad overlap and a stair step effect. This may be a limitation of the “set start and end” node not allowing it to effect verts properly between the start and end points. The reason your other mesh doesn’t have this issue is because there aren’t any verts that need to be properly interpolated. I apologize for the confusion and we may need to investigate a little bit further to determine if this is a legitimate bug. , Ed ---
**Author:** ![anonymous\_user\_0c62419a](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_0c62419a](https://forums.unrealengine.com/u/anonymous_user_0c62419a)\ **Post date:** [April 26, 2017, 11:27pm UTC](https://forums.unrealengine.com/t/severe-spline-mesh-bug-demo-project-included/391269/5 "2017-04-26T23:27:46Z")
Just updating this has been determined to be a bug. You may track it here: [Unreal Engine Issues and Bug Tracker (UE-44425)](https://issues.unrealengine.com/issue/UE-44425) ---
**Author:** ![TaurusI76](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@TaurusI76](https://forums.unrealengine.com/u/TaurusI76)\ **Post date:** [September 19, 2018, 4:54am UTC](https://forums.unrealengine.com/t/severe-spline-mesh-bug-demo-project-included/391269/6 "2018-09-19T04:54:30Z")
If you normalize the tangents, the problem goes away. Like this: ![254059-screenshot-2018-09-19-065038.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/b/8/6/b8615b1aa0b3dac46c738f54a426814f14d25edd.png) So I guess it has something to do with the tangents. Anyway, I’d prefer this bug to be fixed, but this helps as a workaround.