Jael_CA

Ray trace bug in scenes with sun light and Photon Mapping

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I have a problem rendering almost all the interior scenes that involve sun light and photon mapping.

 

The problem is that there are unwanted lights from the edges of some objects and walls. After a lot of research, I simplified the scene to a rectangular empty room with one window:

  • If I place the window on a wall, the photon mapping rendering works fine.

ok.plan (this is the plan file)

ok.thumb.jpg.8d40c5e20402fc43ce45ef8a13f7d02b.jpg

  • If I place the window on another wall, there are unwanted lights in the top edge of one wall.

ko.plan (this is the plan file)

ko.thumb.jpg.3a6e951c12545543dad180723bd5f3cd.jpg

 

I haven´t found a solution (roof, other lights in the room...) beyond not using photonmapping, so I think there's a bug in the photon mapping algorithm.

 

I hope that some advanced user can help...

 

I atach the files with the proof of concept.

 

Thanks in advance,

Jael

 

 

Edited by Jael_CA
I attach the plan files properly to the post

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The attached plans are not there, make sure you close them in CA before attaching.

 

Try some of the techniques described in the posting subject.

https://chieftalk.chiefarchitect.com/topic/14512-lets-ray-trace/?page=4

Starts at posting #88.

 

The relocation of the window and the bleed reduction is interesting. Would need to take a look at that but my sense is that it may have something to do with the angle of the camera in relation to the window/light source. If you were to rotate the camera in the first one to be facing the window as it is in the second one does the light bleed show up. Also, are you using the generic sun or the manually place sun and do you have the sun follows the camera option check on or off?

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I have attached properly the plan files.

 

As you suggested, if I place the camera infront of the window in the first scene (the one that was ok), it turns ko and the light bleed show up.

 

59f655c68185f_previouslyok.thumb.jpg.4ce3b276cd4e3f719bff583d4c4d82ae.jpg

 

I am using in all the scenes the generic sun and the sun follows camera option check is off.

59f655cd9b5bd_sunlightsettings.thumb.PNG.4db39a9db76f7902ca34d118ea7f7ec8.PNG

 

Only disabling photon mapping I get an image without the light bleed.

 

If someone can try the attached plan files in the first post, it would be great...

 

PD: I have to carefully read the post that you suggested because it looks really great!!! Very good job.

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What setting do you have in the Ray trace DBX for the direct sun intensity? In the adjust sun DBX you posted have you tried reducing it's intensity?

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I have tried again putting a roof (a really big one), but nothing changes.

59f970ac72a20_kowithroof.thumb.jpg.2f076507484eb6d4102d1b4794cbbe7b.jpg

ko with roof.plan

 

Reducing the intensity of the sunlight, only makes the problem less evident, but it is not the solution if I want a scene with a vivid sunlight (in the limit, for a zero sunlight intensity, the problem disapeers, but I don't have sunlight).

 

Could you please attach the "ko" plan file with the roof you put on it? 

 

 

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I did not save the plan but I just did the auto build roof and everything was ok, the bleed was gone 100%. Are you saying this does not work in the plan you posted if the only thing you do is build a roof, or is it that after you build the roof you are making  other changes to the suns intensity and therefore reintroducing light bleed back into the scene. The postings I referenced in Let's Ray Trace discusses this.

 

In your scene when I put the roof on the bleed disappeared and also the bright spot on the floor where the sun was coming through the window. The reason the bright spot on the floor disappeared is because your default roof overhang is very large which is putting the window in a shadow. Either reduce the overage depth or change the sun angle to get it back. Take an exterior camera view so you can see the lit and shaded regions of the house to help you see what's going on.

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6 hours ago, Jael_CA said:

I have tried again putting a roof (a really big one), but nothing changes.

59f970ac72a20_kowithroof.thumb.jpg.2f076507484eb6d4102d1b4794cbbe7b.jpg

ko with roof.plan

 

Reducing the intensity of the sunlight, only makes the problem less evident, but it is not the solution if I want a scene with a vivid sunlight (in the limit, for a zero sunlight intensity, the problem disapeers, but I don't have sunlight).

 

Could you please attach the "ko" plan file with the roof you put on it? 

 

 

 Are you by any chance talking about that bright white spot on the ceiling. If so that is not light bleed, it's from the generic light that CA puts into the scene if there are no other lights. To prevent this from happening just put a light fixture somewhere and turn it to off.

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About your comments:

  • "Are you saying this does not work in the plan you posted if the only thing you do is build a roof": Yes, that's exactly what I say :huh:
  • "Are you by any chance talking about that bright white spot on the ceiling.": No, I'm talking about the intersection between the left wall and the ceiling.

59fa0595df97c_kowithrooferrors.thumb.jpg.72bdb0916d8dd815bc9e21605ae88ee8.jpg

 

I know it's an effort for you, but if you could remake the "ko plan" putting a roof on it and post it (I have tried several roofs with and without auto build), I think we could discuss over a valid plan instead of over plans that are not rendering fine :)...

 

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It's no effort. There is no point working with a plan that does not have the issue, I have hundreds of these. We need to work with your posted "Ko with roof.plan" to identify what's going on with it. I'll reload it and take another look. Will be in about an hour as I have some other renderings currently running.

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Ok here it is. I downloaded your original Ko.plan. Placed a camera, no other alterations.

 

Here is the render and it shows light bleed.

59fa1600d7883_Renderkoplanasdownloadedwithnoroof.thumb.jpg.bd18d3394ac19f1acc67b806390683c7.jpg

 

I put an auto build roof on it and rendered it again. No light bleed.

59fa16120f994_Renderkoplanasdownloadedwithwithautobuildroof.thumb.jpg.5a835698947ec73fffe6bc3cb2072b72.jpg

 

Here is the plan with the auto built roof and saved camera view. You give it a try.

Abode_ko plan with roof.plan

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Now you are likely to state that this does not work because you have lost the effect on the floor of the sun entering the window. As I explained in the last paragraph post #7. The sun is still there but it is now not seen as the roof overhang is shading the window.

 

Reduce the roof overhang and there's the sun.

59fa27bb352be_Renderkoplanasdownloadedwithwithautobuildroof_overhangsreduced.thumb.jpg.94dc084f75a61727049c96f7bed14a9c.jpg

 

Better still is to change the sun angle and direction.

59fa27cc03117_Renderkoplanasdownloadedwithwithautobuildroof_sunangleadjusted.thumb.jpg.61643d6e3d190686867949903fb407ba.jpg

 

There you have it, no light bleed and the sun. 

 

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Still not satisfied? Get rid of the generic light, use the ambient occlusion min & max and adjust the image properties a bit.

59fa28c902b15_Renderkoplanasdownloadedwithwithautobuildroof_sunangleadjusted_eliminategenericlight.thumb.jpg.3340110f9de4baec7608a0a17ed72776.jpg

 

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Still not satisfied? Are you kidding? I am astonished with your answers. I have to do some tests to see why my roofs did not work, but it's just what I wanted ... Thank you very much !!!

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1 hour ago, Jael_CA said:

Still not satisfied? Are you kidding? I am astonished with your answers. I have to do some tests to see why my roofs did not work, but it's just what I wanted ... Thank you very much !!!

 

You are more than welcome. From what I saw in your posted plans the problem with the roof was the conflict between the amount of overhang and the angle/direction of the generic sun. As suggested before, shooting an exterior camera view will allow you to see where the sun and shadows are being cast onto you structure, so if the window is completely shaded then little or no light is going to be cast into the interior. Trying to overcome this by just cranking up the sun intensity in the Ray Trace DBX will at some point introduce light bleed back into your scene.

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