When blending terrainThe landscape in your scene. A Terrain GameObject adds a large flat plane to your scene and you can use the Terrain’s Inspector window to create a detailed landscape. More info
See in Glossary in the Forward rendering pathThe technique that a render pipeline uses to render graphics. Choosing a different rendering path affects how lighting and shading are calculated. Some rendering paths are more suited to different platforms and hardware than others. More info
See in Glossary, Unity uses multi-pass rendering to calculate lighting for four layers at a time, and alpha-blends after each set of four layers. In the Deferred rendering paths, Unity combines terrain layers in the G-buffer pass using hardware blending, four layers at a time, then calculates lighting only once during the Deferred rendering pass. The approach in the Deferred rendering paths limits how correct the combination of property values is. For example, pixelThe smallest unit in a computer image. Pixel size depends on your screen resolution. Pixel lighting is calculated at every screen pixel. More info
See in Glossary normals cannot be accurately combined using the alpha blend equation alone, because one terrain layer might contain coarse terrain detail while another layer might contain fine detail. Averaging or summing normals results in a loss of accuracy.