UE4 Surf

could someone explain to me how I can do surf as in CS: GO
something like this

Looking for answer too. All I know is that its difficult, and need to have a knowledge of physics inside ue4 + acceleration

Hmm, why is this off topic. I would suggest have at

float UMovementComponent::SlideAlongSurface(const FVector& Delta, float Time, const FVector& Normal, FHitResult& Hit, bool bHandleImpact)

in the engine source code.