Portals - big difference in lighting

[romullus]

I know that there could be some change in lighting when portals are used, but i didn't expected the difference to be such big. The scene has single big portal, located at the rooftop opening and there's big difference in lighting, mostly visible on the floor. Portal really helps a lot to clean the noise in this scene, so i'd like to use it, but i think that lighting without a portal, looks better in this case. Does such difference looks normal?

Pictures are rendered with minimal tonemapping - just highlight compression, adjusted WB and a LUT. Using a LUT slightly exaggerates the difference, but even without it, it still doesn't look right. denoising and all other effects are turned off.

[Designerman77]

Yes, weird GI behavior when using portals, I also reported to Corona some months ago, providing screenshots and even the scene.

When using HDR as lighting source, portals literally "flip" some rays and you get ugly looking blueish tint in the lighting and strange contrasts in some areas.

I literally stopped using portals because of this.
Working in C4D R20.

I guess in v5 the problem hasn't been solved yet ! ? !

Would be great it Corona development team took this issue seriously.

[steyin]

Looks better with the portals on to me.

[Fluss]

I disagree, I personally prefer the no portal version.

Just a random thought but I always been curious to see if portal normal orientation has an impact on how it behaves. I could have done the test myself but since you have a scene where the impact of portals is quite noticeable... What happens if you flip the normals of the portal? I know Fstorm portals need the normals to face inward (so in your example, normals pointing at the floor), hence my interrogation.

[Designerman77]

I disagree, I personally prefer the no portal version.

Just a random thought but I always been curious to see if portal normal orientation has an impact on how it behaves. I could have done the test myself but since you have a scene where the impact of portals is quite noticeable... What happens if you flip the normals of the portal? I know Fstorm portals need the normals to face inward (so in your example, normals pointing at the floor), hence my interrogation.

Tried this... no effect in my test scenes.
Would have been nice if the solution had been that simple.

[romullus]

Just a random thought but I always been curious to see if portal normal orientation has an impact on how it behaves. I could have done the test myself but since you have a scene where the impact of portals is quite noticeable... What happens if you flip the normals of the portal? I know Fstorm portals need the normals to face inward (so in your example, normals pointing at the floor), hence my interrogation.

That's interesting point. My portal's normals are looking inside (to the bottom), but it's worth to check if things will change if i will flip it. I'll let you know.

UPD: nope, no difference.

[Designerman77]

Just a random thought but I always been curious to see if portal normal orientation has an impact on how it behaves. I could have done the test myself but since you have a scene where the impact of portals is quite noticeable... What happens if you flip the normals of the portal? I know Fstorm portals need the normals to face inward (so in your example, normals pointing at the floor), hence my interrogation.

That's interesting point. My portal's normals are looking inside (to the bottom), but it's worth to check if things will change if i will flip it. I'll let you know.

UPD: nope, no difference.

Such major bugs should be taken more seriously by Corona developers... !

I´d love to use portals again... since they indeed clean up the scene faster in many cases.

[jms.lwly]

I've always found portals to be fairly hit and miss, so tend to never use them... I assumed they were something of the past, but maybe I should revisit.

[romullus]

I've always found portals to be fairly hit and miss, so tend to never use them... I assumed they were something of the past, but maybe I should revisit.

So did i, but recently i tried to put portals in a scene, where i didn't expected much gain from them and was amazed how much quicker noise was going away. So yeah, portals are still very alive, it's just pity that you always need to do tests against no portals and see if they not making things worse.

[romullus]

It seams that in the latest build this issue has been completely solved. YEE-HAW!