in ue 4.27 i have problems with the CustomBrush_Landmass_River on a 8k landscape
fps dropping below 10 a soon as i add the system to the Landscape,
on smaller landscapes i havent seen any problems.
steps to reproduce:
new level
add a Lanscape in 8161x8161 Res with EnableEdit Layers checked
in sculpting tools in the Blueprint section add the CustomBrush_Landmass_River
and then left click in the viewport.