Landscape Tessellation Issue


I was going through my entire material setup to pin point what is really making my level lose so much FPS. I am now surprised to see this. I have put this simple setup below to demonstrate the issue.

Created new material and applied to landscape.

Notice the FPS.

Now I check flat tessellation. Notice I have not tessellated the landscape yet at all. Nothing connected to pins. Wireframe also shows landscape is not tessellated.

Notice the FPS.

What is happening?

go into wireframe mode and you see ^^

It actually does nothing until you give a value to the multiplier pin. So like 70 FPS is being lost for nothing.


I didnt read it properly. Thats quite bad. im sorry D:

Super bump…

Very frustrating issue no doubt!
Did you repro it on a empty scene with just a stock landscape (meaning no heightmap fluff as in your example, just a flat plane) and a simple mat again?
If it happens there as well we can scrape a bunch of options out the book.

Also check these 2 things:

-In render options (project settings) do you have Heightfield GI on? (probably not but just making sure).
-Also in render options (project settings) is dynamic tessellation set on default? (it should be at 48 I think).

Well then uncheck the tessellation in the landscape, the problems with the Tessellation + Landscape are well know. Why you need the tessellation ?

Report this better in Answerhub.

Tried on flat plane in new project, new map. Same result.
No GI.
Dynamic tessellation is set to 48.

Tessellation is vital for me at the moment but still the same huge performance drop without actually witnessing any change.

Just tried this on the LandscapeMountains demo from the Marketplace and I have not much of a performance hit, regardless of flat or pn tessellation.
That’s probably due to my uber GPU though.
What happens if you hook up a basic shader?


Still same drop.
The bigger the landscape, the more obvious the problem becomes. On 2k landscape I almost don’t get that much drop. On 8k landscape I get 70-80 FPS drop. (970 + 4790K + 16GB).

have you tried fiddling around with the lods of the landscape?

I have the same problem. I’ve tried everything I can think of and the performance hit is just too big for landscape. I think I read that Epic is aware of this and they said there is a lot of optimization still to be done. No idea if there are any plans to fix it though. Currently it’s too costly for us to use.

Why you need Tessellation ? Use POM or Bump Map probably better.

@Filly_The_Owl, It helps a little… not that much.
@Hevedy, I need it specifically for blending static meshes to landscape better. POM looks 3D from top down but at intersections with meshes it looks very fake.

Would be nice if at least Epic say they are or are not going to fix this.

POM works fine with for some materials but Dispalcement works better for others and it blends better.

Any Epic word on this? :slight_smile:

I’d like this as well!

Any updates on this?