Hi!
I’ve been working on the new procedural foliage tool that came in 4.8 p4. I have a landscape blended (LB_HeightBlend) with a splat map obtained from World Machine. I have three layers: Cliff, Hill, Flow. I could not succeed in placing the grass on Hill layer only. The grass appears everywhere! Is there a sample like this video: Foliage | Live Training | Unreal Engine - YouTube ?
Thank you very much.
Take one of the Grass types outputs and multiply it by a channel in the splat map then feed that result into the Grass terminator node. This should only allow grass to spawn in the masked areas. There is a tutorial that goes over this but it has not been released just yet. But when it is head over to the Tips & Tricks section and check out the Texture Based Masking for the Grass Tool section for more information about how to go about doing this.
Thank you very much Sam! Just multiplying and connecting did not work. I subtracted the other two channels from the Hill now it is perfect! But the grass appears on my roads. The road is build by Landscape Splines attaching a Static Mesh. Masking solves the problem but is there an easy way? 
As a result I copied my green channel to a new image in PhotoShop. I took a high-res screenshot of landscape from top view scaled to the size of my splatmap and placed as a layer under the new image. Then I erased all the road sections. This took couple of hours. I will be happy to know if there is an easier way 
Thanks!
I am not sure if Landscape splines are taken into account or not as I never tried them when I was doing R&D for the tutorial. I will try and ask Ryan B today as he is man when it comes to this type of stuff.