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View Full Version : HDR in Photos and 3d, somebody help me.


rafamathard
02-26-2011, 03:42 PM
Ok, i have a simple question but i can't find an answer anywhere ( tried and google and found nothing).

I know that hdri, in photography is when you take photos at different exposures and use the differences in the darkest one and the brightest one to make a image with a...high dynamic range, right? ok...so why is hdr for 3d made using a reflective sphere? what is the difference? are they the same thing? why not just use photos with different exposures in 3d too? please help.

michaelaaut
02-26-2011, 04:31 PM
this tutorial has 8 chapter - it describes the whole process shooting your own hdr and using them in 3d.
it might answer all your questions:

http://www.cgarena.com/freestuff/tutorials/misc/photoreal/index.html

InfernalDarkness
02-26-2011, 09:21 PM
Really, the purpose of using HDR photography in 3D is generally as a light-map, a file that drives Image-Based Lighting (IBL). You need a full 360 sphere to make this work properly, or at least a skydome (top half of a sphere). Thus, you need a 360 image which you can map to this sphere.

You don't need an HDR image to make this work, but using one means you have a much higher range of light and dark of course. In 3D, this light data can help drive photons for Global Illumination, sampling for Final Gather, or anything else you want to plug this data in to. (in Maya, specifically) So it's better to use an HDR because this simulates sky lighting much better than an LDR image does.

rafamathard
02-27-2011, 02:06 AM
thanks alot for both answers im already devouring that tutorial and my mind is much more clearer on what hdri means.

CHRiTTeR
03-13-2011, 06:43 PM
the sphere has nothing to do with hdri directly...


the sphere is only used because it makes it easier to capture envirements


Hdri in photography and 3d are the same thing (high dynamic range image)

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