Spline in editor doesn't get updated by BP

When you modify any spline point in your BP construction script the spline in the editor will not get updated accordingly but the added/changed spline points in the BP exist but not visible and not editable. Like there are then 2 splines, the modified one through the BP and the default spline visible in the editor. So it is impossible to modify a spline through the editor and through a BP. I don’t see the reason behind this behaviour so I guess it is a bug.

Hi ,

If you move the spline does it fix the adjusted points? If an actor is already in the level and the construction script is altered, it will not reflect the changes until it has been moved/altered in the level viewport. The construction script only runs when an actor is destroyed and recreated or first created.

I know, I can see when the construction script runs. That is not the issue here. This has to do with it: Construction script ignores components changed in the map - Programming & Scripting - Unreal Engine Forums

To clarify a spline that is generated only through values in the BP can not be adjusted in the editor with moving spline points around because of this issue.

Have you pressed compile after making adjustments? On my end, if I make an alteration to a blueprint construction script containing a spline, the spline updates after I press the compile button. Do you see this occurring on your end? Have you tried in later builds to see if this is occurring outside of 4.8?

Hi ,

We have not heard from you in several days. I am marking this as answered for tracking purposes. If you are still experiencing this error, please comment with the requested information.

I have the exact same problem in UE 4.11.
This is driving me crazy: generating a spline via construction script, I can edit the spline in the editor (drag the spline points around) but the spline mesh doesn’t update to the changes. It really seems there are two splines, the one reacting the the construction script (add spline, add spline points, add spline mesh component, set start and end …) and the one with the spline points dragable in the editor.
By creating a public array and filling it with the refference to the splines created, it seems that each time the construction script fires, a new spline is created. The LAST element in the array always was “SplineComponent_338”, while the other elements were populated with “TRASH_SplineComponent_XYZ”.
When adding a spline point in the construction script and the blueprint actor was placed into the level, both the spline and the spline mesh had the same path, but when changing the spline by dragging it’s points around, the mesh did not follow. Even after recompiling the blueprint with the construction script, both had different paths.
Just to make sure: the construction script saw to destroying old spline mesh components and redrawing them. With a spline added with the “+ Add Component” button, the construction script worked fine.
I do not see this problem as resolved,

Hi Stoon82,

Do you have a project this is occurring in that I can take a look at? I checked the bug report in Davsision’s previous comment to be certain, but that bug was closed as it appears the transforms of instance components are run after the construction script is rerun, not during, so if it is a similar issue you may be reaching one of the limitations of construction scripts.

I am facing the same issue as well in 4.11.2 . My spline up didnt get update via BP construction script. I did a couple of DarwDebugLine !to confirm that! The yellow line at spline(0) is the up vector direction. The subsequent spline up should line up nicely at blue/pink line but it didnt update. alt text

Edit: Sorry, my bad!!! I was using “get up vector at spline point” instead of the correct “Get spline up dir”. Everything is doing alrighty for my side.