HDR's for Exterior Scenes

[craiggorton]

Is it useful to try to use an HDR of a sunny day, with some clouds, to light an exterior scene and to be the background, too? I would think this would be great, but I haven't found a working solution.
I tried some of the HDR's from here: http://www.evermotion.org/index.php?...fold=exclusive
The color images really seem to make the whole scene very blue, and the intensity is very high.
Should I use .455 gamma for environment lighting and backgrounds?
Anyone have a test scene they'd like to share? I don't really need any geometry, just the HDR's and how they're set up.

Thanks,
Craig

[craiggorton]

Re: HDR's for Exterior Scenes

Okay, I'm re-reading Micha's exterior tutorial. Is it really not possible to use an HDR for the lighting? Maybe there is a lower contrast one I could use?

Thanks

[dalomar_cg]

Re: HDR's for Exterior Scenes

Exteriors and HDRIs are usually a bit of a balancing act for the simple fact that most HDRIs can't represent the brightness of the sun effectively. So beware of trying to only use HDRs for exteriors. Usually you have to adjust how much of the sun versus how much of the HDR actually influence the lighting of your scene. A bright summer scene is going to be much different than a cloudy day. As far as gamma correction you don't actually have to adjust the gamma value for HDRs because that format only uses the gamma value for display purpose as opposed to using the gamma value for the actual color info like jpgs or pngs.

[Micha_cg]

Re: HDR's for Exterior Scenes

A high contrast sun at a HDRI is useless. I don't know why it is possible to download this kind of HDRI. It cause strong noise or very long rendertimes, because the random GI sampling dosn't know, where the small sun light point is placed. If we use a directional light, than the Vray engine know, a small light source is placed at xyz and must not search it with random sample rays.