Render Region can speed up your work flow when you just want to test out how a section of your scene looks like without having to render everything. It is also helpful for minor correction provided you do not change the camera position. Set a render region and the once you have the render sequence overlay that with a composite program. Saves a lot of time for last minute changes or silly pick ups after an animation sequence has been rendered.
Hold Ctrl B and Left mouse drag an area, this will set the region to render.Press F12 to render.To cancel the region hold on Ctrl and Left Mouse drag a larger area beyond the camera view space. [...]Selecting GPU or CPU rendering in Blender 2.8:If you have a supported GPU, change this in the Render panel under the Device section. If no GPU is detected the this field will grey out.GPU renders a lot faster than CPU. Blender 2.8 supports most Nvidia cards because it was built to run with CUDA cores. The latest Nvidia RTX cards are also supported however at this time the benefits of RTX for quicker raytracing render speed is not supported. I believe this is currently in development to be implemented in future Blender updates, possibly in 2.9 or later.For the artist using newer iMacs, the AMD Radeon card is not supported. From what I [...]
