Rendering ROI?

I can't seem to figure out how to render just the Region Of Interest.

I want to do a test render of a particular part of a shot, so that the file size is small.

I can define a ROI, but am not sure how to tell the renderer to render only the ROI area.

How do you do that?

If you're using the RoI tool in the viewer it's only for the viewer.
If you want to render out only a part you can use the crop tool but Fusion will process all the pixels above the crop node if any node requests all the pixels of the image (but I think the nodes does that also with the RoI tool...)

Thanks for the reply, Jacob Danell...

Ya, I had a feeling that's how they did things... Wierd. With other apps, you can do a whole 'render region' that works both in the viewer (speed up workflow/preview updating) as well as the render itself (renders just that area... both in terms of processing the image AND the resulting screen render size.

Yep, I did get around that currently by creating a small sized background, and merging the full size comp into that, so only a part of it was visible... and rendered that.

Seems a bit of work just to do that. Odd that they don't just have the ROI work in the render, too...

Ah, well...