Night rendering with hdri sky

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Permalink Reply by Render Plus on January 22, 2011 at 8:17am

The Tone Op Brightness control is the brightness slider at the top of the rendering window:

 

Slide it to the left to make the scene darker.

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Permalink Reply by Alain Bonnefoy on January 22, 2011 at 9:46am

Ok but this is to be used if I'm outside but if I want to be inside but want to see outdoor buildings by night so by using TIIF at night from HDRi 3?

Al Hart said:

The Tone Op Brightness control is the brightness slider at the top of the rendering window:

 

Slide it to the left to make the scene darker.

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Permalink Reply by Render Plus on January 22, 2011 at 2:01pm

The brightness operator can be used for all scenes.

 

However, if you want to balance artificial lighting against light from outside (e.g. HDRI sky or scene) you are better off to use lighting channels - so you can use the sliders to adjust the effects of the different types of lights.

 

You will still need the Brightness slider - because it effects the overall brightness of the entire scene. If, for example you used lighting channels to cut the sky brightness by 50% and then used the artificial slider to cut the artificial lights by 50%, then the automatic Photometrics would brighten the entire scene - and would look just the same again. You would have cut the brightness slider by 50% to achieve the effect you desired.

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Permalink Reply by Alain Bonnefoy on January 22, 2011 at 3:32pm

Ok, I'm going to look at it.

Regards,

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Permalink Reply by Render Plus on January 23, 2011 at 3:50pm

Here are 3 images of a simple rendering using Tiff at Night and two ceiling lights.

 

These will give you and idea what you can do with lighting channels, brightness and contrast.

 

The first is the default rendering

 

 

The second has the sky intensity (the HDRi image) turned down and the lights turned up.

 

 

The third then increase brightness and contrast using the Tone Operator.

 

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Permalink Reply by Alain Bonnefoy on January 24, 2011 at 1:01am

Ok Al,

Thanks a lot

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Permalink Reply by Christopher Alan Krupp on January 31, 2011 at 11:24am

Alain:

 

I do pretty much what Al has suggested. Use artificial lighting for the interior and the sun and sky settings in the lighting channels to set the over-all scene effect you want. Brightness slider is an important element. Turn the sun off and set the sky down way lower as well. The sky setting seems to have the most affect.

 

You also can add a night background in the Background dialog box (jpg, tiff, etc) to the drawing so that what is see outside is whatever you want. If the background doesn't show set the Y-off in the Background dialog box to a (-) minus number to get it to move up in the drawing/rendering until it's visible.

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Permalink Reply by Alain Bonnefoy on January 31, 2011 at 11:48am

Thanks a lot Chris,

I got quite good results.

 

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Permalink Reply by Christopher Alan Krupp on January 31, 2011 at 2:36pm

No problem..figure you may as well get the benefit of my endless experimental hours.

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Permalink Reply by Render Plus on January 31, 2011 at 11:05pm

We recently added another feature which I don't think anyone has tried yet.

 

If you create your background image with the horizon centered vertically, and turn on auto-horizon we will adjust the image to the center of the image matches the horizon in your model.

 

check Adjust Center Line to Horizon on the Background Setup Tab.

 

(This works best for interior scenes which view the background through a window, but where the horizon is based on the interior view desired)

 

Image with horizon in vertical center

 

 

Christopher Alan Krupp said:

You also can add a night background in the Background dialog box (jpg, tiff, etc) to the drawing so that what is see outside is whatever you want. If the background doesn't show set the Y-off in the Background dialog box to a (-) minus number to get it to move up in the drawing/rendering until it's visible.

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Permalink Reply by Christopher Alan Krupp on February 1, 2011 at 8:34am

Al:

 

I don't get the "create your background image with the horizon centered vertically" statement you just made:

 

How do you create a background image? I've been simply selecting jpg's from my library of images, not creating anything. Are you saying that the image be cropped such that the horizon is mid way between the bottom and the top of the image?

 

I think I recall trying the check box a while back.......it didn't seem to do much of anything for an exterior rendering. Maybe I missing something here.

Chris

 

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Permalink Reply by Render Plus on February 1, 2011 at 9:36am

One obvious way to create a background image is to take your camera outrside and shoot a photo. If you point the camera at the horizon then the horizon will be in the vertical center of the image.

 

Another way, as you mention, is to crop an existing image so the horizon is in the center.

 

What we did for some existing cityscapes was to expand the image by adding dummy, or dark areas to the bottom to move the horizon to the center. (When you crop, you lose part of the image. by adding more the the bottom you get parts you hope you don't see.)

Here is an example:

Image of Denver Skyline. Lines have been extended from windows, and other lines which converge at the horizon to locate the horizon.

 

Image with horizon at center of image.
(You can place the horizon at the center by enlarging the image in a Paint Program, shifting the image so that the horizon is in the center, and adding additional color above or below the image to complete it. Or by cropping the image so that the horizon is in he center.

 

SketchUp model looking out a window with the horizon just above Susan's head.

 

Rendered scene with background adjusted to match the horizon. Note: from this view the black we added at the bottom of the screen is not visible.

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