I have a number of problems with landscape splines in a project that contains a landscape that was created by import of a heightmap so it is not a flat surface (like ik all the video tutorials).
Regardless a layer is set to spline-only or not, I can select single points and move them, but the terrain is not deformed.
But after I have selected Select all control points, or all segments in Tool Settings, or in the details panel it is no longer possible to move any point of change tangent. Adding points, or undo placement still works.
This occurs for existing landscape splines and new ones.
I tried this also in a new level with a flat world (as in the video tutorials) and here as well, the same happens. The only difference is that when a point is raised or lowered, the landscape is indeed moving with the spline if the layer is set to “Spline-only”. Removing this restriction removes the updated terrain (all raised and lowered terrain returns to flat) but the spline stays as it is.
Even after deleting the layer and creating a new one, points will not be accessible for moving, whether the layer in which the splines are created, is set to spline-only or not. Not even during creation of the spline, thought new points can be created, or points can be deleted. Nor does removing the level and do the same in a new level.
Only after closing the project, and restart it, the situation is cleared and I can create and edit splines again via control points - until I select all control points or segments. This selection cannot be undone, the only way to undo the selection is to close and reopen the project.
It sounds like you’re encountering a technical issue with Unreal Engine related to landscape splines and control point selection. To address this problem:
Try updating your Unreal Engine to the latest version. Newer versions often come with bug fixes and improvements.
Check for any specific plugins or assets you might be using in your project that could be causing conflicts or issues. Disable them temporarily to see if the problem persists.
Review the landscape and spline settings in your project to ensure they are configured correctly.
If the issue persists, consider reaching out to the Unreal Engine community or support for assistance, as they may have encountered similar problems and could provide more specific solutions.
Save your work regularly to avoid data loss when you encounter such issues.
Unfortunately, it’s difficult to provide a simple solution for such a technical problem, and you may need to go through a troubleshooting process to identify the root cause and resolve it.
It happens in both 5.2 and 5.3, both the latest versions.
The only additional plugins I use are PCG (and related) and Kitbash3D’Cargo
I use default settings, in project and test levels. The main difference is that in the project level, the landspace is imported (Gaea heightmap, scaled up).
I already do.
I found out that selecting a segment will disable selecting a single control point. The only thing you can than do is change the length of the segment. So the real issue is that when one a segment, all control points or all segments is selected, control points are no longer accessible for movement of rotation, and that this setting can only be undone by closing or opening of the whole project .
But also, that the landescape is lowered or raised when a control point is raised or lowered, but not aside the whole width of the spline - but that can well be a matter of settings and the place the spline is located; plus there is space between the mesh and the landscape; Lowering a point will - in most cases - also lower the landscape, so it is impossible to lower the spline exactly onto the landscape. Most notable after a mesh is applied to all segments:
To get the meshes on the landscape, set every control point to not to lower the landscape but at some point and lower the point. However, on some larger segments, the landscape is still lowered
Have you got “raise terrain” and “lower terrain” ticked under “landscape deformation” for the spline segment you are modfying, if not then the landscape won’t move, and if it is, it will ALWAYS move the landscape when you are trying to get your spline to match…
Another thing I found, is that the resolution of your actual landscape (when you created it) can be a problem with getting it to conform to a spline, as effectively the spline (when using raise / lower) (i think) is “pulling” at grid points on the landscape to move it towards your spline… If you had infinite resolution then it would always match the landscape!
As far as I know the Spline is attempting to move the landscape to be at a tangent to the spline, and if there aren’t enough points (or maybe enough control points on your spline!) to “pull at” then if will get close to, but NOT exactly fit to the landscape!
Sometimes it just doesn’t play nice, and u have to frig around… I have plenty of “rubbish” strewen around bits where I just couldn’t get it to fit to hide gaps lol! :o)
You can also try setting the mesh offset in the settings i think to lower it more, but in quite a few cases I found I had the raise the landscape to the best of my ability manually, and/or ADD more control points to get a better fit, plus altering the rotation of the segment where you are going ACROSS a hill for example but the hill is falling steeply in the other axis direction!
