Direct Override render slow

[PTMV]

Hello everyone, I have a problem that I don't know if this is normal, I had never paid attention to it, I used a black color in the direct override visibility to be able to remove the Background more easily in post, but what I noticed is that when I use this feature, the rendering time goes up a lot, in comparison the rendering without it was taking around twenty-five minutes, and with this feature activated it went to an hour and twenty minutes, is it normal for the rendering to increase in time with this feature active?

[romullus]

If you're using noise limit as stopping condition, then this increase in render time might be expected. Corona evaluates noise differently when the image is predominantly dark or bright. This has been reported and discussed on the forum multiple times, you can try to use search and see if you can gather some useful info about that, but as far as i'm aware, if you want consistent render time, it's better use pass or time limits as stopping conditions.

[Avi]

Hi,

You can go through this forum as it was discussed before. This is also already logged in our system.

https://forum.corona-renderer.com/index.php?topic=41960.0

(Report ID=CMAX-1323)

[Otuama]

I assume that would also be the reasoning behind Render Selected taking longer too.  We also find we need to bring the noise limit down too.

We find it quite annoying when rendering fixes that firstly it takes longer to render (because it's taking the black areas into account) & as a result of this, the areas we do want rendered are more noisy.

Where possible I try to use render regions in the animation but this obvs isn't possible 90% of the time.

Is this something that could be looked into?

[TomG]

Primarily, Noise is not always a good choice for a render stop, and Passes and Time are a better choice in some circumstances. Think of it like getting 5% of a pizza - what that means will depend entirely on the size of the pizza, while getting 107 grams of pizza is always the same regardless of pizza size. And with Noise, it will depend on what types of area are included too as those will contribute to the % of what is clean and what is not. You can submit a feature request on https://chaoscorona.ideas.aha.io/ though to see if this can be improved in some way.