sIBL usage - balancing the lighting and sky

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Marcel2586
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Re: sIBL usage - balancing the lighting and sky

Postby Marcel2586 » Tue May 31, 2016 12:59 pm

Remember this settings. i realy like this picture
this would be funny if it weren't happening to me :shock:

pciccone
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Re: sIBL usage - balancing the lighting and sky

Postby pciccone » Tue May 31, 2016 1:10 pm

Hi Russ.

The issue here is not that the LuxRender is not capable of handling the map.
What we have here, is a very high contrasty, HDR image, with direct sun in it. In a similar situation in real life, with a real camera, you would have exactly the same issue. Given the high contrast of the environment, you would be forced to either expose for the subject or to expose for the environment. You might also want to check the value for gamma used with IBL. It might be set to a value that is causing this issue.

Cameras, real or virtual, have a much more limited latitude than the human eye. The range is in fact less then half. For this reason you cannot light a scene using simply natural light and respect the same result that you experience with your own eyes.

For example, when the shooting interior scenes where windows visible, Hollywood cinematographers generally apply a darkening film on all the windows, because otherwise they would be blown out when exposing for the subject.

So, how do we solve this issue when using the map that you are trying to use?

The solution is actually rather simple, you place the blame primitive in front of the subject, between the light and the subject, but behind the camera. You then set the plane to be of type architectural Glass, and set the transmission texture to use a medium gray color. This trick basically creates a set of "sunglasses" for the whole figure, so that it's not overexposed anymore. Then you adjust the exposure for the environment. Once you do that the figure might become overexposed again. If that's the case then make the glass pane darker.

Hope this helps.
--
Paolo

RLSprouse
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Re: sIBL usage - balancing the lighting and sky

Postby RLSprouse » Tue May 31, 2016 1:57 pm

Thank you so much, Paolo. I think this is the kind of advice I was looking for. When I tried to use a diffuser, it ruined the shadows. But using a darkened glass material makes sense, as that would not diffuse the shadows. I will give it a try.

~ Russ

RLSprouse
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Re: sIBL usage - balancing the lighting and sky

Postby RLSprouse » Tue May 31, 2016 2:39 pm

That did the trick! Thanks, Paolo. So simple, once you see it.

~ Russ

pciccone
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Re: sIBL usage - balancing the lighting and sky

Postby pciccone » Tue May 31, 2016 2:41 pm

You're very welcome.
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Paolo

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Fram1963
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Location: Ottawa, Ontario, Canada

Re: sIBL usage - balancing the lighting and sky

Postby Fram1963 » Tue May 31, 2016 2:49 pm

This should be move to "Tips, techniques, and recipes"...

Cheers,
Lyne
:D

pciccone
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Re: sIBL usage - balancing the lighting and sky

Postby pciccone » Tue May 31, 2016 2:51 pm

Yep
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Paolo

RLSprouse
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Re: sIBL usage - balancing the lighting and sky

Postby RLSprouse » Tue May 31, 2016 2:59 pm

Interestingly, I am getting a lot of white speckles on V7's skin using this setup. I often have some minor speckles in shadow areas, but in this case, even though I have waited for 3.5kS/p, there are a lot more white speckles than I usually see.

Any thoughts on this?

~ Russ

V7 Dutch Sky test 8.png

pciccone
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Re: sIBL usage - balancing the lighting and sky

Postby pciccone » Tue May 31, 2016 3:24 pm

That is the result of the material. I thought that she was quite shiny. Can you post the material definition for the face?
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Paolo

RLSprouse
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Re: sIBL usage - balancing the lighting and sky

Postby RLSprouse » Tue May 31, 2016 4:10 pm

It is just V7 with the V7 preset being applied in Reality. Is that what you mean?

Specular is V7FaceMapS_1001.jpg
Glossiness: 7012 horizontal, 6000 vertical.


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