Our friend the manual says: When rendering into a texture, the camera always renders into the whole texture; effectively rect and pixelRect are ignored. That is a very weird limitation. There are plenty of effects that would take advantage of rendering into only a portion of a render texture, and it's hard to imagine there's much (or any) more to it than rendering into a portion of the screen. So, is this correct? Why? Is there some other way to render directly into a portion of a render texture in Unity? Thanks.