burned out areas

[Crayox13]

Hi guys,
I've been struggling with this on many of my scenes. On the attached scene I have a room pretty much exposed the way I want it to, maybe a bit lighter, but of course the window area is way too bright. I use lwf. The scene has vray sun with its sky in vray environment for GI and refl. I use linear exposure and tright reducing bright multiplier to even 0.2 but at this point I get strange dark halos on walls, I guess where the transition between light and dark is....but still I don't get a nice exposure on window. I tried going even lower - to 0.02 but then my whole scene darkens, not just window area. Am I missing something I should do here? Of course I can use VFB curves but there's gotta be a better way to "clamp" those areas.
thanks in advance

[glorybound]

I guess you have to think like a photographer. If you were to be in a room, without lights, and take a photo looking towards a window, how would it expose.

What I do is, save my image as a 32 bit exr and with masks, expose the outside and inside differently.

[joconnell]

I guess you have to think like a photographer. If you were to be in a room, without lights, and take a photo looking towards a window, how would it expose.

Brand new man

[glorybound]

I am a little thick, but once it gets in, watch out!

[samuel_bubat]

That´s basically the reason I don´t use Physical Cameras. They are very limited. A realistic image doesn´t necessarily needs to be
Photorealistic. Realism and Photorealism can be two completely different things.
But to solve your problem. Try "Reinhard" color mapping.
This gives you a pretty detailed control about brightness vs. contrast in a scene (low burn value/high mulitplier).
With Reinhard Colormapping you can theoretically get a large room with a tiny window nearly white
without burning the areas around the window (and without using any other fakes like wrong GI Multiplier or dummy lights).
Using Reinhard will usually wash out your textures because it can produce a pretty extreme color curve.
So you´ll need to correct them in the opposite direction. I usually just use the "Output" curve of a Bitmap Map to do this.
You of course can use a physical camera and Reinhard. But it´s like turning the same knob in two different places.
Reinhard Multiplier is basically the same as adjusting the exposure within a Camera but a camera lacks the burn value.

edit: I attached an example of a room lit by a direct light and environment gradient only through a small window.
(no physical sun, no physical camera, no LWF). No color value reaches pure white.

[Crayox13]

Thanks guys...interesting point samuel. I'll try reinhard.

Glory, the problem here also is that the burned part is inside. Luckily it's rectangular so I could easily render a dark version and PS it, but that doesn't seam elegant and the right way to do it, especially if in the future I have a complex area that could not be PSed nicely.

[Zdravko]

There are different ways to handle burn out areas. Since the problem is the huge brightness difference which V-Ray try to handle, you can clamp the output (if you don't need that additional light information) or use additional lights in the room just like the photographers do. The aim is to balance the lightning in order to avoid huge brightens contrasts. In real life all that burn out areas gets blurred by Bloom or Glare lens effects.

The black edges that you get on your window edge looks like a filter issue. Do you use Catmull-Rom filter?

[raymarcher]

In real life film sets these problems are the same, there they put filters on the windows.

you can always put your vraysky in the vray environment override and plug that vraysky in an output map lowering brightness and placing in standard 3ds max background.

[Crayox13]

I don't use any filters - that black edge is actually a part of the window.
Reducing sky intensity would linearly reduce all the lighting so I don't think that's a solution, I need to adjust the balance.

I'll try clamping or reduce burn value when I get back to that scene.

[svetlozar.draganov]

Hello Crayox13

Did you get the result you want ?
Please let us know if you still struggle with it.