Micro collisions on Landscape with physical sphere

Hello,

A video is better than my explanations, so here is my problem : 2018 05 31 12 40 36 - YouTube

It’s a fresh landscape, I’m trying to visite it with my sphere “physics simulated” and I can’t find the answer to the problem. The sphere is jumping, like rolling on a small collision line. I think it’s a problem between the landscape tiles / components but I’m new with UE4 and I have no other ideas. The “player collision” or “visiblity collision” views show nothing wrong.

I don’t know if it’s a collision problem and why if it is. I did nothing but create new landscape, sculpt and paint.

I can’t understand. I created a new landscape and played without a problem yesterday, I “saved all”. Today, I launch my project by modifying absolutely nothing, and the “jumping problem” is here.

Two basic features, landscape and simulated physics, and it’s not compatible. It’s annoying.