Blur GI and light leakage

[re:FORM]

Sorry if this has been discussed previously.

I am having real difficulty achieving a good interior render without light leaking in through all the corners. After much experimentation, I have isolated the Blur-GI parameter as the culprit. The only way I can find to remove the leakage is to set this parameter to 0. I can't believe this is right as the default animation setting has the blur-gi set to 8.

Is there another parameter that would allow me to keep the blur gi up at 8 without suffering from this light leakage?

Thanks in advance for your advice.

[jacksc02]

do you have any moving objects in your scene?

[cpnichols]

Maybe a stupid question, but did you try "check sample visiblity?" It may help with your light leaks.

[vlado]

Re: Blur GI and light leakage

Sorry if this has been discussed previously.

I am having real difficulty achieving a good interior render without light leaking in through all the corners. After much experimentation, I have isolated the Blur-GI parameter as the culprit. The only way I can find to remove the leakage is to set this parameter to 0. I can't believe this is right as the default animation setting has the blur-gi set to 8.

Is there another parameter that would allow me to keep the blur gi up at 8 without suffering from this light leakage?

Nope. Setting Blur GI to more than 0.0 will produce light leaks around thin walls. If you don't want this effect, set it to 0.0 or make the corners with thick walls. The "Blur GI" setting is mostly useful for animations of moving objects, which have small details that may flicker from frame to frame. In all other cases, set it to 0.0.

Best regards,
Vlado

[re:FORM]

Thanks for the feedback everyone!

Nope. Setting Blur GI to more than 0.0 will produce light leaks around thin walls. If you don't want this effect, set it to 0.0 or make the corners with thick walls. The "Blur GI" setting is mostly useful for animations of moving objects, which have small details that may flicker from frame to frame. In all other cases, set it to 0.0.

So, is the light leakage connected to the scale of my model?

If I have to reduce blur gi to 0, then I need to bump up the other parameters to smooth out the gi solution. Can you recommend the best way to do this without vastly slowing down render times?

do you have any moving objects in your scene?

I am not animating any objects, just the camera.

Maybe a stupid question, but did you try "check sample visiblity?" It may help with your light leaks.

I did set "check sample visibility" but it had no beneficial effect.

[TishoChaos]

Set Blur GI to 0.0 and follow the tutorial about Walk-through animations in the Online Help - it offers a useful and fast way to render animations with moving camera.

[re:FORM]

Thanks, I have used the walk-through tutorial, but I was curious as to why the light leakage wasn't a problem with the model in the tutorial. What is it about my model that causes the problem? Does the model in the tutorial have overlapping surfaces(thick walls) to avoid the leakage?

Is it prefereable to overlap walls (which leads to a less clean model) or to drop GI blur to 0.0 ?

I'm just interested to find out what the best workaround to this problem is.

Thanks again!

[vlado]

In the tutorial, Blur GI was set to 0.0 (we used the High preset), so that's why there are no problems there.

Best regards,
Vlado

[re:FORM]

OH, I'm sorry! ... I missed that when I scanned through the tutorial again...

DOH!

[re:FORM]

Ok. i've been having a bash at the tutorial again and was wondering what settings for the irradience calc would be best.
The tut states " 3.2. Make sure the irradiance map Interpolation type is set to Density-based. This will enable the irradiance map to pick the closest available samples from the cached solution."

...but the interpolation type does not have this option (it's under sample lookup" , which interpolation type should I use in conjunction with density-based sample lookup?

(I am using v.1.47.03)

[vlado]

They are basically all default settings, so the Interpolation is "Least squares fit" and the sample lookup is "Density based".

Best regards,
Vlado