Hi, first of all I absolutley love Corona…the engine 
Insted of using the standard max render window to correct regions, maybe there is a posibility to implement a render region to the CFB. I like to be able using the post processing options during test renderings without having to switch back and forth.
Thanks
You can still use the render region in the viewport to adjust it, without having to change VFB’s.
cheers
My Wife was going on about this, she wants a render region in the Corona frame buffer too 
make it like Vrays one too but with multiply regions at once.
cheers
Yesterday I discovered you can use render region in standard max’s VFB when using Corona. Just uncheck “custom vfb” in “Main Corona Settings” tab. -_-
maybe I miss something but render crop is not working? can you add this?
Thats the recommended solution until I implement better VFB 
Hey!
I know this is a quite old topic, but I just wanted to chime in and let you guys know, that I’m looking for something like this. So now, if I want to render a smaller region of my render I have to switch back to my max window, have to select the required viewport, than have to open the render settings window, after that, usually switch a tab to the common settings, than select the region option from the dropdown menu, than go back to the max window, and try to look for the corners of that nearly unvisible rectangle, to somehow select the desired region there …
I don’t want to seem like somebody, who is whining, just tried to describe, that how complicated it can be, to render a quick region. And just one half of the problem is the speed of the process, what is the most bothering in my opinion, is that as I mentioned earlier it is hard to see where the sides of the region-selection rectangle are exactly in the viewport and usually you can select the desired region of the image better in the frame buffer.
In my opinion something similar, what we have in Vray should work fine.
So +1 from me for this request
I added a Shift+R shortcut to “select render region” (not sure about the name but you’ll find it), so I simply press Shift+R, adjust the region size in viewport (come on, it’s not that hard to grab those handles), press F9. If I want to render the whole image again, I either change render mode to full image or adjust the render region to cover the whole viewport area and press Shift+R again. For me it’s super fast. Of course integrating this into VFB would make things even faster and easier.
I would like to see the VFB improved a bit
It’s something I really liked about vray, having the side menu where I can save tmp renders, and load them up (when comparing before/after)
totally love the render to region function directly on the vfb, super fast to turn on/off, and i can select the region directly on last render
as other suggest, there might be workarounds to make this work, but I was told that the biggest advantage about Corona should be it’s simplicity , and to me it’s much more simple to press button, then setting up hotkeys.. etc
Actually Maru solution is the best and fastest one.
I tried to set the Shift+R shortcut and it is great.
I think that setting the region on the last render is definitely better but, for now, we can use this solution until Ondra will update the frame buffer.
I don’t know if it is possible, but setting multiple region or polygonal regions would be even greater!!
to anyone looking for the name of the command for setting up this shortcut, it’s “Edit Render Region”.
Rawalanche, can you explain better? =)
Also, do you know how to create a shortcut to oper Corona VFB?
Thanks!
Ondra, where does this stand in the Corona roadmap? Anything to pop up soon? Thx!
will be released probably tomorrow