Cycles Cut-Away Preview

Maybe this has been asked a million times already but…

Back in the day.
Using Blender 2.49 you could select a square area in you scene and make a render preview of just the selected area.
What are the options in Cycles?

Tired of rendering a whole scene to see my editing.
View port rendering is not exactly what I’m looking for.
Looking for more of a section of the camera view.

Ctrl-B, drag a rectangle around the area you want rendered.

Steve S

If you know 2.49 then you obviously know border rendering. It’s just like that but visible in the 3d viewport. Both for cycles and the blender render

Thanks everyone. I knew it had to be there someplace.