Strange blowout on wall

[johnharrison]

Hi. I've encountered a strange problem with the lighting on my wall. I'll post 2 images with different objects close by the problem area, showcasing how the light behaves.

 

I have tried applying a standard grey material, which had no effect. If I move the wall placed left of the windowpane, the problem disappear because there is nothing to cause a problem. The wall pictures has also had a standard grey material applied to it. No other blowouts of this type has appeared any other place in the scene. As you can, there's not really any high intensity exterior lighting going on either. The brick texture and the problem texture is the same object, I've just done as much "debugging" as I can, but my expertise ends here.

[notamondayfan]

Instead of using standard materials, always use vray materials.

 

Next to try to narrow down the problem, you need to look at the render elements and see which pass the blowing out is happening. If it's in the raw lighting pass then there's a light hitting that area. If it's in the reflection pass then it's reflecting something bright. If it's in the raw global illumination pass then it's a GI issue, which could be numerous thing.

 

Have a look and let us know.

 

Dean

[johnharrison]

Hi Dean. By standard material I actually ment standard vray material, so that's what I've been testing with. I've also checked my passes and the blowout definitely happening in the rawGI pass.

[Chris MacDonald]

If it's in the GI pass I'd bet money it's your irradiance map settings.

 

I'll bet if you just turn on "detail enhancement" it'll help a lot.

[johnharrison]

Thanks for suggestion, I came to that conclusion myself but did some tests, and I've also done a test now with medium irradiance preset and a 100 sphere subdivs, but no change. Detail enhancement didint seem to produce any visibly better results either...

[Chris MacDonald]

Does it occur when you use brute force?

[johnharrison]

Yessir. I tried Brute Force as primary and both primary and secondary to be sure. Still there.

[Chris MacDonald]

Then I suppose it must be a light leak. Do your walls have a thickness, or are they a single plane/spline extruded upwards?

[johnharrison]

I've now not only tried to cover all potential light leaks with planes, but also added shell modifier to the objects in that area. No luck. :/

[easy3dsource]

Judging by the things you've already tried, my guess is that your wall material might have some glossy reflections, and you're seeing the reflection of a light somewhere in your scene?

[johnharrison]

The first image is the whole scene with a grey standard vray material override, but without the glass in the window. The second is with a plane covering some of the window, but you can see something happening there aswell, just not as intense. :/

[Stephen Thomas]

Are you using a vray plane light placed inside the window? If so it could be that it is just very near to the taller box, causing light to bounce back onto the wall.

[johnharrison]

No attempt of any "portal lights". This issue is really annoying, guys!

[Ismael]

Post the scene. Your persistence inquiring on this issue guarantees someone will look at what you have and help you out.

I personally cannot see above Max2010 and V-Ray 1.5.

Note:

"Similar to the photon map, you can get "light leaks" with the light cache around very thin surfaces with substantially different illumination on both sides. Sometimes it may be possible to reduce this effect by assigning different GI Surface ID's to the objects on both sides of the thin surface (see the Object settings dialog); the effect can also be reduced by decreasing the Sample size and/or the filtering."

 

Vray Object Settings

"GI surface ID - this number can be used to prevent the blending of light cache samples across different surfaces. If two objects have different GI surface IDs, the light cache samples of the two objects will not be blended. This can be useful to prevent light leaks between objects of vastly different illumination."

Edited May 10, 2013 by Ismael

[johnharrison]

Good idea, Ismael! I had a look at GI Id's, and had a render test with the wall's GI ID set to 1 instead of 0, but no change.

 

Here it is!

 

3ds Max 2012 with vray 2.30.02

 

http://www.filedropper.com/projectgalloway65

Edited May 10, 2013 by johnharrison

[Ismael]

I'll take a look this evening unless some friends here have time and check on it before that.

 

Ok, tried to look at the file but it is too advanced (2012).

Edited May 10, 2013 by Ismael

[johnharrison]

Ugh, I'm sorry Ismael. I could always save it as a 2010 compatible file, but my vray version is 2.30.02, which I guess wouldnt work with your 1.5 version?

[Ismael]

Try saving it as 2010. I think the problem is the higher Max version.

[johnharrison]

3ds max 2010 compatible

 

http://www.filedropper.com/projectgalloway652010

 

There you go, let me know if you have any questions.

 

Tex and project files.

 

http://www.filedropper.com/projectgallowaytextures

Edited May 11, 2013 by johnharrison

[Ismael]

As the Max file came without resources (maps,etc.), I just textured a similar floor and brickwall. Removed one of the 2 V-ray domes and left only one used to display an environment HDRI. Removed the Environment Cylinder with V-Ray light material you had in there. Placed a V-ray Sky in the V-Ray :: Environment rollout (GI Environment (skylight) override). The Sun intensity reduced to 0.01 as is used only to mark the floor. Added a 'grass' V-Ray plane. Added a V-Ray Physical Camera for control F=8, SS=5, ISO=100. No, those are not Daylight settings for a 'real' camera... Changed Color

mapping to Linear 1,1,2.2 with Affect background and Don't affect colors (adaptation only) checked only.

 

That aside, I never saw the problem you displayed even when I first tried with a material override. Be back later. Cheers.

 

[johnharrison]

I'm wondering, Ismael, if it could be as easy as the blowout is the result of the hdri hotspot (sun) coming in from the left of the windows, abit left of the camera's direction, and blowing out the white of the wall, which in turn spreads GI all over the nearby wall. Eh, I'll draw something.

[Ismael]

Yes, the lighting. Look forward to the finished scene.