Light Interior

Hey,
I have big problems with my Interior
Scenes to illuminate correctly. If I use HDRI
it is very bright outside but the interior is relatively dark.
If I increase the brightness from the HDRI is nice and bright interior
but outside it is only white. Should i add sun or area lamps?

you can have simply two brightness values for your HDR, and switch them with the ‘Is Camera Ray’ from the light path node.
(you may need to use portals to speed up convergence)

And for a final touch, you can use some invisible lamps to raise light in the interior scene, create moods, or pull attention to some parts of your scene.

What Secrop said. But technically it is the correct solution that there is big brightness difference between outside and inside. Your sRGB monitor can display about 7 stops of dynamic range, but difference between indoor and outdoor can be much bigger. The result is either correctly exposed indoor and very bright outdoor or vice versa. When shooting live the solution would be to shoot with a camera that is capable of recording higher dynamic range and then compress the highlights. You can do the same in Blender. Do a highlight compression or some kind of tone mapping after rendering.

Some of the first visual effects in film where to composite an outdoor image into a window due to the exposure problems of filming with a real window. So, using the camera ray trick would be very similar to what has been done in film for years. But, you don’t want to throw away too much light information. That is where kesonmis’ suggestion comes in regarding compressing the highlights.

The easiest way to do this is to use the color management in the scene tab of the properties window. You can set the render view to “film” rather than “default”. The film color transformation logarithmically compresses the highlights like real photographs do. This puts more stops in your image (stops are a measurement of light range that photographers use, basically). This will give you a very natural looking compression quickly and easily. If the image is too dark, you can increase the exposure. If the window is still too bright, use the camera ray trick to change the strength of the HDR lighting when he camera looks at it directly. Gradually reduce the strength of the camera’s HDR until you get something that looks natural for whatever you are trying to do.

If you want to compress the highlights more or manually, you should enable the curves in the color management. Setting the color of white will color-correct and scale the light in your scene. This may darken your render too much, so you need to use gamma and the color curves to brighten the shadows. Don’t bother increasing the exposure here since it will also brighten your highlights, which defeats the purpose of trying to compress them. Shaping the curve to look like a logarithmic curve will compress the highlights. You can make this manual adjustment using the default color transformation or the film color transformation.

Glad I stopped by since this is a informative thread. Austin my understanding is on the old film sets they used sheets of neutral density filters on the windows to avoid overexposure.

It would have been more accurate for me to say “what was done”. It was a very early process (long before color even). Other methods were developed later. It is mentioned here:

I have not studied methods for this in depth, so I had never heard of what you mentioned. And, I expect that the filters you mention would cover the windows.

I have looked at this issue in more depth.
This is a photography guide on shooting with windows in the shot.
http://improvephotography.com/36784/6-ways-to-photograph-interior-windows-in-real-estate-photography/
It suggests:

  • Increasing the flash to equalize the interior light with the outdoor light
  • Closing the blinds on the window
  • HDR Tonemapping
  • Adjusting the levels of RAW footage in Lightroom
  • Wait for the dawn or dusk
  • People in the comments (and other sources) suggest using Photoshop to replace the overexposed window with an outdoor photo (or with a properly exposed photograph of the window).

This is a filming guide on shooting with windows in the shot.
http://www.mediacollege.com/lighting/background/windows.html
It suggests:

  • Increasing the room lighting
  • Reducing the light through the window by using a filter

I will put these into perspective regarding what we have to work with.

  • If our interior is only lit by the window, we can’t increase the lighting independently of the window. But, if we have interior lighting, this could be an option. If we don’t have lights inside, we could add lights in the interior just for the purpose of increasing the lighting. This is what MZGarmi originally asked about. But, that can look less natural (if not placed correctly) and take more time than other options.
  • Closing the blinds or reducing the light from the window would only work if the scene is not being lit by the window. This is basically the reverse of increasing the brightness of interior lights. For digital scenes, the difference is trivial since light strengths are easy to change and especially since ray tracing noise is independent of light strength. You can think of less exposure in a real camera as being the same as less samples in Cycles.
  • HDR tone mapping uses an algorithm to maximize the contrast in localized regions throughout the image. Usually this is done using 3 images of different exposures to fill in shadow and highlight detail. But, the principle can be applied to a single standard image. It can also be applied to a single HDR image (like a RAW). Many people, including myself, don’t like the unnatural look that these algorithms give. Blender does not have this “feature”.
  • This is what we are talking about when we talk about adjusting white levels and compressing highlights.
  • This is effectively the same as (2).
  • This is the same as using the camera ray trick.

I still stand by my suggestion, which is a combination of (4) and (6). And, I suggest using the “film” transformation and setting a pleasing exposure as a good starting point before adjusting the white level and modifying the color curves.