VRay Light Leaks

[Julio Verani]

Hello people

 

In the image below, there's a model of a window that i made to use in most of my projects. In this render it is quite clear the problem i'm facing lately, the light leaking and irregular shadows are not helping me.

 

https://imgur.com/a/nbn5T

 

Can anyone lend me a hand? I already tried tweaking the light leak parameter, tried increasing values of interpolation samples and hemispheres (which helped a bit, but with values of 250 or more for both).

 

Thanks in advance.

Edited October 17, 2017 by jverani

[heni30]

Try making the material a Vray Override material; then make the the GI material a dark gray color vray material.

[Julio Verani]

Try making the material a Vray Override material; then make the the GI material a dark gray color vray material.

 

 

https://imgur.com/a/G9tGA

Like this?

[heni30]

No. You're base color in this image is dark gray.

 

Base color should be white; GI color should be gray. Just look for a tutorial on "how to prevent color bleeding".

Edited October 18, 2017 by heni30

[Julio Verani]

Hi George,

 

Sorry, i didn't get what you meant...

 

Now i figured out, thanks a lot!

 

Vray OverrideMtl with dark grey on the GI spot, worked like a charm!

(It was my first time with this kind of shader)

 

https://imgur.com/a/A88IV

[Francisco Penaloza]

Actually, that light bleed could be for a few reasons. The geometry is open or there is space between the shapes or your interpolation is too big.

Usually Light cache.

An easy way to check this is to do a render region only using brute force. If everything renders fine then you know it is your GI settings. Otherwise, you are using a too bright white color or the geometry is wrong.

 

Interpolation helps you to 'smooth' light sample, but the drawback is you lose details on small crevices like windows frames.

 

If you are using Irradiance, you need to reduce the sample size and increase the sample count. adjust the interpolation as need it, other quick solution could be to check the box 'detail enhancement' this will brute force those small areas.

Then check your light cache setting, reduce the interpolation number, or uncheck pre-filter and check the retrace.

[heni30]

Fco - I think you have just recruited a new convert to Corona!

[Francisco Penaloza]

Fco - I think you have just recruited a new convert to Corona!

 

lol

well, the funny thing is I never had that problem, and I mostly use default values on VRay 3.x

[Dejan Sparovec]

Yeah, you can try a couple things to get rid of that.

I would do a checklist in this order and try a test render after each one:

1. Light Cache: turn on Retrace.

2. Light Cache: turn on Leak Prevention

3. Irradiance map: turn on Detail Enhancement.

4. Irradiance map: turn on Check sample visibility.

 

All of these things, except maybe leak prevention, will increase your render times. You can also try to lower their default values if you really need to.

Edited October 20, 2017 by mali22

[Julio Verani]

Actually, that light bleed could be for a few reasons. The geometry is open or there is space between the shapes or your interpolation is too big.

Usually Light cache.

An easy way to check this is to do a render region only using brute force. If everything renders fine then you know it is your GI settings. Otherwise, you are using a too bright white color or the geometry is wrong.

 

Interpolation helps you to 'smooth' light sample, but the drawback is you lose details on small crevices like windows frames.

 

If you are using Irradiance, you need to reduce the sample size and increase the sample count. adjust the interpolation as need it, other quick solution could be to check the box 'detail enhancement' this will brute force those small areas.

Then check your light cache setting, reduce the interpolation number, or uncheck pre-filter and check the retrace.

 

Thanks a lot Francisco, i will study all your recommendations for sure. I made a big mistake by using the same settings of other pro scenes for my own, but now i learned that a scene is mostly never the same as any other, so, the settings change, even a bit for best output.

 

Thanks a LOT!

[Julio Verani]

Yeah, you can try a couple things to get rid of that.

I would do a checklist in this order and try a test render after each one:

1. Light Cache: turn on Retrace.

2. Light Cache: turn on Leak Prevention

3. Irradiance map: turn on Detail Enhancement.

4. Irradiance map: turn on Check sample visibility.

 

All of these things, except maybe leak prevention, will increase your render times. You can also try to lower their default values if you really need to.

 

Will do Dejan, this checklist only adds up to my new references, and i will check all of it, definitely!

 

The only thing i don't understand is this "Leak prevention" thing, since it is always on (i never disabled it) no matter how i change its values, the result appears to be always the same, weird..