Do portals make a substantial difference?

[Rhodesy]

Im a C4D lurker and have tried the beta quite a bit but not on a full scene. In the tests I've noticed that you get a very heavy speed penalty the smaller the windows and the more indirect lighting you have for interiors. This makes sense as its relying on light bounces to resolve the image and a lot will be wasted bouncing around the outside of the building that can't be seen. Hence why portals are used as far as I can tell. Vray doesn't have quite the same slow down - there are other issues with artifacts but not quite the noticable slow down with smaller appertures. So Im interested to know how much of a difference portals make to corona and if you can get acceptable render times in these tricky scenes? Thanks.

[Cyanhide]

Honestly call me a fool, but at times I feel portals produce more noise/increase render times. I am to lazy to actually spend the time and test it but something is certainly feels that way.

[Rhodesy]

Oh right that's good to know. I do find the quality and speed of Corona fantastic but that seems to be heavily related to opening size in my tests. I do quite a few basement fit outs, often multi level that rely on light wells so its something to consider.

[maru]

Here is a guide on portals:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000501660
They work best with small windows.

[Rhodesy]

Thanks that's a good link. Looks like they do make some difference if you're careful. Looking forward to trying them on C4D when they get implimented.