The terrain_global_base material provides several parameters for fine tuning of terrain geometry optimization, shadows and LOD blending:
- Subpixel Polygons Reduction parameter determines the minimum ratio of polygon size (in the screen space) to the area seen in the viewport. This parameter allows you to remove too small polygons that are barely visible, in order to increase performance.
- Back Face Culling parameter is used for culling of the tessellation patches that have their back faces turned to the camera. The number of polygons can be significantly reduced (e.g. culling back faces of a large mountain) and increase performance.
- Frustum Culling Padding parameter is used to control culling of the tessellation patches outside the viewing frustum.
- Shadow Offset parameter enables to adjust the look of shadows in cases low-poly LODs cast shadows on high poly LODs in areas, where there should be no shadows should.
- LOD Padding parameter can be used to adjust smooth transitions between terrain LODs and increase performance.
In case if your terrain does not require insets, you can disable this option to increase performance. To do so, just uncheck the Use Insets in the States tab.
Also you can use frustum culling optimization to affect performance: enable the Fast Frustum Culling option in the States tab. This option increases the number of culled polygons.
Using Occluders for Terrain#
To optimize rendering of the terrain, you can use the Occluder Terrain node. It allows you to cull invisible parts of the terrain: these parts won't be sent to GPU. However, the effectiveness of the occluder terrain depends on the scene content and the terrain relief.