Thanks Romullus for always response, yeah I meant blocking the sun with geometry to achieve the cloudy day effect and focusing the sun on specific areas of the scene, I didn't mean the eclipse effect. The problem I am facing in corona is that this method doesn't work very well when there is volume fog in the scene, also big sun size that's necessary for soft shadows makes it worse, there's a lot of light diffusion in the scene which covers the blocking geometries making them practically useless, so it won't be possible to focus or limit the light to a specifc area. If you decrease the sun size it will be easier to get more directionality but the problem is that the shadows will become sharp and that's not desired for an artistic cloudy day soft mood.
Despite Corona, GI is very weak in Blender Cycles so it's really easy to block the sun by placing some geometries in front of it because there's almost no light interactions in Cycles which makes it good for that sun blocking purpose!