Black gridlines in shadowed areas of terrain mesh

I’m having an issue appear when I bake lighting for my terrain. I’ve tried multiple light types and settings, including the experimental GI solution. They all give me these seams along the terrain sections. Can anybody shed some light on this?

Hey MOP88,

In order to assist you with this issue I am going to need some more information. Going under the assumption you are using lightmass to bake your scene…

  • Have you rebuilt your scene using the ‘Build All’ option?
  • Would you mind showing me the settings for your Directional light as well as your skylight?
  • Was this Landscape imported from a file, and if so, what type of file did you use?


Hey Andrew,
Apologies for my delayed response. In my frustration, I re-built the scene entirely and started having BSOD crashes every time I would build the lighting. It seems that a fresh re-install of the drivers has fixed it. The new setup for the terrain is:

*Imported an r16 file from World Machine, with three separate weight maps.
*A stationary directional light and a movable skylight
*Atmospheric fog component

Unfortunately, while I don’t get seams anymore, I now get these splotches of light in side the “solid” shadowed areas, with only the edges casting accurate ones.

Hey MOP88,

Click on your landscape actor itself and try changing the ‘Static Lighting’ resolution.

I would also take a look into using you Cascaded Shadow Map and Distance Field Soft Shadow settings. Both of these shadowing technique can improve the quality and performance of your shadows with a large Landscape.

Take a look at the documentation for both and attempt to find the appropriate settings that you find visual pleasing at the far and near distance.

Ray Traced Distance Field Soft Shadow

Cascaded Shadow Maps

Let me know once you have gone through these documentation pages and have attempted to apply these techniques. The issue you are seeing could be just that you shadow distances and settings are not set up properly.

Thank you,

The documentation is proving itself very useful. I have solved my issues by doubling the resolution of the static lighting, and I’m starting to plan for clouds. Long distance partclie lighting and shadowing will be next. For now, everything works. Thanks!