4.8 Adaptive Tessellation Problem


I’m getting weird adaptive tessellation cracks in 4.8 P4 (near the edges of the screen) as I move the camera around.
It’s noticeable with an ocean shader with vertex displacement.

It’s important to note that the exact same material setup worked fine in 4.7.

I made a post about this problem in the forums as well (check out the thread for screenshot and more details).

Here is a test project so you can guys see the problem easier:


Hi TK-Master -

Thank you for the sample project. I was easily able to see the issue and have reported it as UE-16291. I will keep you informed as we work toward a solution.

Thank You

Eric Ketchum

Hi Eric, sorry to ask about this already but are there any news on this? I’m asking because 4.8 is right around the corner and this really breaks up my ocean.
Am I going to have to potentially wait till 4.9? that would be sad :frowning:

Hey TK-Master -

This should be fixed in 4.8 Release. But it has been fixed by adding a new Controller in Tessellation called Max Displacement which you can set to counteract the non-tessellation. I tested this on your ocean shader and it fixed things up nicely.

Eric Ketchum

I have the similar problem and it seems that it isn’t solved in 4.8 version. Here is my post - [HELP] Geometry issues - Community & Industry Discussion - Unreal Engine Forums

Eric, could you tell us more about how to use the new controller? Should we put it in the material?

I think that I fixed the issue. Found the controller in the details tab of the material and set it to 100. Also turned on the Crack free Displacement just in case. Thanks for the tip Eric.

Yeah setting the max displacement to 80 or higher seems to fix the problem for me! thanks Eric.
Not sure if there are any side-effects if you set it too high… what does that parameter do exactly?

I could confirm the presence of the same bug in 4.18, however Kvazimodo’s fix have successfully solved my issue