sampling based on alpha mask

[koznarj]

Hi,

for exterior renders with a decent amount of sky visible, it's very efficient for speeding the render up to create a render regions for sampling only the areas that are needed - so to say exclude the sky from sampling..

Most of the time, this corresponds with alpha mask of the scene ...

Would be very very useful to be able to just "enable sampling based on alpha mask" in one click.

While working mostly in architecture with geometry in perspective, crating the regions is very very boring...

See attached image.

[maru]

Does it actually work? Have you measured the render time differences? Corona has a feature called adaptivity which should do exactly this - less samples should be spent on sampling the areas where it is not needed.
The reason why some areas always need to be sampled (sky, solid background, etc) is that there might be some small object there. If we don't sample that area, we will not see that object, or it will be a pixelated/noisy mess.

[koznarj]

I would say it does work. I haven't measured it though. I can do it..

What about once render mask is enabled?

Example: I have a window in a scene and just want to "fix" something in the reflections.. So I add this window object into a render mask, hit render. Let's say the area of this window in the final image is 5%. Once I "focus" the rendering onto this area where the window is located, the calculation speeds up very much, you can see the difference with a naked eye... in comparison while no render region is defined..