1. From the camera view, hold down CTRL and then press B (you will notice a dotted target line).2. To start your render region, Left click and drag and then let go of the left mouse button to end the point. You will notice a red dotted line, this is the area Blender will render your scene.3. Go to Render > Render Image on the top panel or press F12 to render your selected region.
How to deselect the render region in Blender 2.9?1. From the camera view, hold down CTRL and then press B.2. Draw a region larger area than the camera render view box (The outer dotted box) by Left click and drag and then let go of the left mouse [...]
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. [...]