Spline mesh isnt casting shadow when RHI DX12 and Ray tracing is enabled? 4.23

Created a basic spline mesh and the mesh isnt casting a shadow. Disabled ray tracing and the shadow was being cast. Is this a bug with 4.23?

I have the same problem in 4.24.2.

Splines aren’t supported yet for Raytracing

Is this still the case? I have a translucent material that works fine on static meshes but on a spline it fails to appear entirely.

Raytracing is suppose to be production ready with the recent release of 4.25, so it would be odd if it didn’t support something as core as splines.

I still can not get Spline Mesh Components to cast shadows with Ray Tracing Activated. As the above post states, it seems odd this is omitted from a production read feature.

Same in 4.26, no raytraced reflection or shadows for spline meshes sadly.

Also, just wanna say it’s odd with how much splines are used in the new Landmass and Water systems, but ray tracing isn’t supported. Maybe I’m missing something, considering Fortnite now supports ray tracing and it uses splines everywhere on the map.

My best guess is the difference is the splines used in these systems aren’t rendered the same way that splinemeshcomponents are. Still, sad to see they aren’t supported. Pipes, wires, and roads seem like pretty standard and common use cases for splines and surely it looks odd when those objects in the scene are missing shadows or proper reflections.

Maybe there is a hybrid ray tracing mode that defaults to old render methods for components that don’t support ray tracing? Cause that would be a nice bandaid.

Yeah it would be great to get the benefits from both “worlds” and to have raytracing support all the engine features.

How can we report this? I think its a necessity. I imagine its not so hard to achieve!

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grab all the splines and Merged them, as it does not lose its shape. it will convert spline actors to a static mesh and cast shadows while Raytracing is enabled.
As,‘Convert to static mesh’ option deletes all spline points.


Just spent the whole day trying to understand why a set of fences was casting shadows in preview lighting but not after lighting was properly built. Literally been hours trying option after option. Finally stumbled on this thread. Just adding a voice I hope Epic will heard… it’d be awesome if this issue was fixed.

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thanks for this, literally saved my day.

Big Thanks form KOREA
You saved my life!

Is this still the case now (Unreal Engine 5.0.3) does anyone know? Seems to still be an issue specifically when I turn on ray traced shadows with spline meshes but just want to check I’m not missing something.

On the latest version of UE4 - 4.27.2, shadows for splines do not work when tracing rays. I’m making a product for both UE4 and UE5, it looks like I’ll have to abandon the abundant use of splines when working with RTX.

Thank you for sharing the problem, otherwise I would have had to look for solutions for a long time, spend a lot of time on it and not achieve results.