Texture displacement not working on spline?

Development Asset Creation
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1

Hi,
I’m trying to apply some displacement on a spline path but it is not working.
I’m using UE version 5.3.2

Here is my landscape spline:

image
image1900×911 134 KB

I applied a mesh to all segments, with a material instance. I have boosted the displacement effect to show that it is working on the mesh:

image
image1903×897 213 KB

But there is no displacement on the segment.

However, If I attach a mesh to the control points, there is a displacement effect:

image
image1909×911 127 KB

Sorry I’m still pretty new to UE, so pardon me if I’m doing something stupid.

How to get the displacement on the segment?
Thank you for your help.
Valou