In ver. 5.8.3, creating a Landscape Spline mesh using a mesh that has obvious Z height results in the mesh being compressed in Z
Please select what you are reporting on:
Creative
What Type of Bug are you experiencing?
Assets
Steps to Reproduce
Create a minimal Blender road mesh: any aspect ratio in X & Y, low Z perimeter walls. Example mesh used was approx. 127 x 127 x 12.5 cm
Apply All Transforms and export as FBX
Using the imported road mesh, create a Landscape Spline Mesh
Set Spline Mesh Settings to Scale to Width off and Scale = 1, 1, 1
Add the same mesh to the level as a stand-alone instance
Expected Result
You should expect to see results similar to those shown in the attached image.
Observed Result
Note that the mesh is compressed in the Z direction by a factor of around 9.
This factor can be estimated by positioning the stand-alone instance of the same road mesh side by side to visually compare with the landscape spline mesh version. Also shown in the image is the same mesh used with a custom spline mesh blueprint which shows no Z compression.
The Z compression factor seems to be lightly correlated to the XY aspect ratio. If the road mesh’s X length is 18 times the Y width, the factor was slightly above 9. But if X =Y, the factor drops to around 8.6.
The obvious short-term work around is just use landscape splines for landscaping and add all above ground details using a spline mesh blueprint.
The factor you measured is the landscape spline still scaling the mesh by control-point Width. A new landscape spline point defaults to about 1000 uu wide. Your mesh is about 127 uu across, and 1000/127 is about 7.9, which is the 8.6 to 9x squash in the screenshot. Scale to Width off is supposed to skip that, but on 5.8.3 the mesh entry still writes that ratio into the spline-mesh up scale (the Y of Start Scale / End Scale, which is world Z). A normal Spline Mesh component never does this, which is why the blueprint looks right.
Check these in order:
Select the spline points, not the mesh entry, and read Width. If it is around 1000, set it to the real mesh width (127) on every point. That field is the full width, not a half-width.
On the mesh entry, Forward Axis has to be the road’s length axis. For a mesh modeled along X that is X. If it is Z, height is treated as length and you get this exact flatten.
If you do not want to retune every point, set the mesh entry’s Scale Z to the factor you measured (about 9) and leave X and Y at 1. That only holds if the factor stays the same along the whole spline.
Keep the blueprint spline mesh for anything with real height (curbs, walls). Use the landscape spline to deform the terrain, and drive the blueprint from the same points if the two need to match.
Also open the static mesh and check the bounds are really about 127 x 127 x 12.5. The landscape path uses those bounds, so a bad import scale shows up here and not on a spline mesh you scaled by hand.
