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View Full Version : Can a mia_sun_sky render be considered as an HDR image?


royterr
04-28-2009, 02:32 PM
if i render a 32 bit openEXR. image with the mia_sun_sky node:
wouldn't that image be considered as an HDR image since it has many levels of exposures stored in it?

lazzhar
04-28-2009, 02:56 PM
Yes it isan HDR image (http://en.wikipedia.org/wiki/High_dynamic_range_imaging), wherever you are using mia sun&sky or just regular lights or non of them.

royterr
04-28-2009, 03:09 PM
Yes it isan HDR image (http://en.wikipedia.org/wiki/High_dynamic_range_imaging), wherever you are using mia sun&sky or just regular lights or non of them.

Ok i undestand.
So what's the main difference between using a mia_sky_sun system or an HDR sphere and rendering a 32bit openEXR image?

lazzhar
04-28-2009, 04:45 PM
It's about the lighting you are after.
With Sun&Sky you can simulate a lighting condition of a specific time of the day and have accurate intensities and tones.
In case of a sphere you should map something to it. If it's an HDR image prepared for this purpose it should give you the exact lighting of the set where it was taken in.
In theory, you try using a fisheye lens shader in mr, use physical sun and sky in a blank scene and render out to 32 bit HDR. The you could use this output as a texture mapped to a sphere to light your scene. However due to a limitation in MR you will not get similar results.
I was curious to try out this using 3delight with en envlight shader and the result was very similar to rendering straight from mental ray with its physical sun and sky.

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