Road splines are deforming the terrain in a weird way, is there a fix?

I’m working on an offroad racing game, and using splines to create a road that deforms the terrain is giving me a very bumpy road that is unpleasant to drive on when the road banks too much:

A few things to clarify:

  1. I think there is enough density in the landscape geometry to rule out this being a faceting issue.


  1. Smoothing the landscape with landscape smoothing tools doesn’t fix it.

  2. I would prefer to not use a mesh road in this case. As a last resort I might be able to do that and disable its rendering but I prefer if there was another option as the bumps would still be visible.

I feel like maybe the resolution at which the road spline raises and lowers the terrain is the culprit but I can’t find a setting to modify this.

Putting some information here in hopes that it helps someone in the future. We are using a custom version of UE5 based on 5.1. I had a coder I work with take a closer look at this. This appears to be a problem in the rasterization of the geometry of the spline to the heightmap, possibly a bug in the triangle rasterizer. The simple rasterization that UE5 uses now won’t work for anything more than just gentle curves and definitely breaks down fast with any kind of banking curves. This is the type of problem I started with:

We are now adding another subdivision on top of this. Getting better:

This also seems to address another issue with problematic road offsets that I mentioned in another post here. Road collision and spline seem much closer now:

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