Improving the quality of a specific part of an image?

odastein

I already had this problem several times when while the overall rendering is fine, one or several spots in the image stay noisy. Apart from using an extremely long rendering time so that even those spots will be rendered properly, is there a way to adress this issue? A shortcut to render better a small portion of an image? 

Leana

You can use the spot render tool to render a specific portion of an image, so maybe you could re-render those sections only (it should be faster than the whole scene) and then composite them with the original image.

odastein

Leana said:

You can use the spot render tool to render a specific portion of an image, so maybe you could re-render those sections only (it should be faster than the whole scene) and then composite them with the original image.

I'll try that. Thank you. 

What should I raise in priority to remove better the noise? Convergence %age? Image quality? Something else? 

odastein

I'm doing it, but I see a problem, however...The spot render will render in a very small size (a small portion of the work window), and even if it's rendered very well, once enlarged to fit the size of the overall image, the definition will probably be very low...

odastein

Indeed, I got a super small spot render, so, the resolution isn't sufficient to merge it with the overall image (unless I'm missing something wrt how to proceed). 

Leana

I don't remember where it is exactly but there's a setting to get the spot render tool to render to a new window and not the viewport, in that case it is rendered at the same size as the section would be in the full pic.

odastein

Leana said:

I don't remember where it is exactly but there's a setting to get the spot render tool to render to a new window and not the viewport, in that case it is rendered at the same size as the section would be in the full pic.

Ah! I'm going to try to search for that. Thank you. 

Richard Haseltine

Leana said:

I don't remember where it is exactly but there's a setting to get the spot render tool to render to a new window and not the viewport, in that case it is rendered at the same size as the section would be in the full pic.

Tool Settings pane.

odastein

Leana said:

I don't remember where it is exactly but there's a setting to get the spot render tool to render to a new window and not the viewport, in that case it is rendered at the same size as the section would be in the full pic.

Richard Haseltine said:

Tool Settings pane.

I finally left that image the way it was, but I've now used it to correct some part of a render after it was finished. Neat. Thank you for your answers.