Limited Region

Limited Region support for FPrime Render. In the simplest mode, this is just like LightWave's limited region, allowing you to render just a portion of your image. But FPrime Render is a progressive renderer, so limited region can be used in much more powerful ways.

In one new mode, you can choose to refine just a limited region. This may work well if you have an image which needs more "cooking" to remove radiosity or texture noise in one area but not everywhere. You can now guide FPrime to work only on those areas. This can be repeated many times for different regions (even overlapping ones). This mode can also be useful to initially render a small portion of your image to determine a goal quality level. After you've found the level, you can turn off limited region and FPrime will work on improving the rest of the image without wasting the work already done.

You can also use limited region to replace a section of a previous render, especially useful for print resolution rendering. Imagine you have a poster sized render of a fire engine, but after rendering, you realize you need to add a flag to the back of the engine or update a decal on the side. You can make the change to your scene and set a limited region that covers the changed area. You can then have FPrime replace that region with new, a new re-rendered pass. This is similar to the old manual solution of rendering the limited region as a new image and compositing the replacement area onto the old render. The big common-sense caveat to this mode is that the re-rendered changes need to be local. If you change a light intensity which affects the whole image or have long shadows or radiosity which responds to a distant object, or use FPrime's 2D blur modes, the net changes aren't local, so rerendering just a limited region will not work, you need to rerender the whole image.