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-   -   create hdri? (https://simplymaya.com/forum/showthread.php?t=19969)

mc-fleury 22-01-2006 07:15 PM

create hdri?
 
how do i create an hdri with my own pictures.ex:i take a picture and i want to make it an hdri.how do i do that.i google searched but i didnt fing anything.i already saw a great tut here but i cant remember where.

pbman 22-01-2006 07:21 PM

wiv lots of work
cant remem where the tut was either but u have to takes lots of shots wiv different exposuers as far as i can remem
good luck and also find some more info before u start

MattTheMan 22-01-2006 07:22 PM

You need a shiny, reflective ball, like a silver Christmas Ornament or a mirror ball. You take your digital camera, and you take pictures of the ball in different exposures, I think 8 is enough. then you take all of those into Photoshop and you make sure the ball is the only thing in the picture, on each of the exposures. Then, you download HDR Shop by doing a Google search for HDR Shop Download, and you use the create HDRI from image sequence, you load all of your exposures, you assemble the HDRI, and then you go to Images-Panorama-Panoramic Transformations- and on the right, you make it a Latitude/Longtitude, with the default size, usually is enough, and you press ok.

then you save that as a .hdr image. I hope you know how to use the HDRI in Maya, right?

hope that helps;
cYa LaTeR,
MaTt :alien:

mc-fleury 22-01-2006 07:32 PM

yhea for sure i know how to use hdri but is there another way of doing an it as i dont have any mirror ball.

MattTheMan 22-01-2006 07:35 PM

no christmas ornament?

gster123 22-01-2006 07:38 PM

try using Spherise in photoshop, then cut the image so that the ball section is the only thing in the picture

Pyrus 22-01-2006 07:49 PM

Yeah, great summary Matt :beer:

Here you can find additional infos on how creating "REAL" panoramic HDRI.

Technical infos
http://www.cgtechniques.com/tutorials.php
("How to create HDRI dome" tutorial is another explanation ... like the one from Matt (http://hdrshop.com/ too))

Some really good and famous ones ...
http://www.debevec.org/Probes/
http://hdri.3dweave.com/library/
http://tengaal.art.chez-alice.fr/Pag...rage/hdri2.htm

Lots of them there ... no need really to create yours hehehehe.


These are also usefull (not relative to HDRI) but environments panoramas. With a bit of tweaking and toshop, I usually get great 360*360 to be used as backdrop (reflections) or just as environment background.
http://www.meteobelgium.be/gallery
http://www.1000skies.com/fullpanos/index.htm
http://www.bretagnepanoramique.com/payscornouaille.htm


Some last ref I advise you.
It's mainly talking 'bout IBL New Maya7 Node and some plugs and additional tools.
http://www.thereisnoluck.com/plugins_iblTools.php

mc-fleury 22-01-2006 07:59 PM

thanx guys for taking the time answering me.:)

mc-fleury 22-01-2006 08:20 PM

if i already have my image do you know how i can ajust it so it becomes an hdri.

gster123 22-01-2006 08:29 PM

Download HDR shop.

For a true HDR image you will need a series of pictures at different F values (explosure settings).

mc-fleury 22-01-2006 09:36 PM

what are these differents values

Pyrus 23-01-2006 12:09 AM

Hehehe Gest, explosure, I like the typo :beer:


Yo Mc Fleyru
http://www.mir.com.my/rb/photography...huuterdial.jpg
Using one of these values on a standard one, you'll have the LDR (low dynamic range) images you need, the exposures.

Or on your digital cam, you can have them (but not as much) ... the values are 100-200-400, usually, if i'm not wrong.

And here are the transformation process, summarized.

Quote:

HDRShop allows you to create a high-dynamic range image from a sequence of standard 24-bit images taken at different shutter speeds. The images should be taken without moving the camera, and should be bracketed so that the darkest parts of the scene are clearly visible in the longest exposure and the brightest parts of the image are not "blasted out" to white in the shortest exposure. ...
...

Summary : You need a serie of pictures with a standard camera. Several exposure times. 8 is optimal, but i think 3 would be a good start. Don't think about playing with the contrasts and brightness in toshop, from a standalone photo, ... the result looses a lot and lighting will be pale. Here you can see the result , with one photo. Well, it shows clearly why hdri stores color values with a 32 bits floating precision, for each RGB (so the 96 bits compared to the original 24 bits image(s), 3*8 bits) http://gl.ict.usc.edu/HDRShop/main-pages/intro.html .

So IF you got at least 3(8) photos with different exposures, than you can assembly the serie with hdrshop, here's how http://gl.ict.usc.edu/HDRShop/tutorial/tutorial3.html

After all that, you got some HDRI map you can use for lighting, but not a true environmental/reflectable panoramic HDRI. I mean a .hdr file you could map on a sphere without any distortion. Having such panorama, is one step up in the creation of real env. HDRI.

You'll often read about mirrored ball. And here's the technique http://gl.ict.usc.edu/HDRShop/tutorial/tutorial5.html that will provide best results.

So to your question MacFLeury "is there another way than with mirrored ball ?" ... yes, if you got several exposures, at least.


Hoping not leaving too much errors or typos :blush:

mc-fleury 23-01-2006 02:37 AM

thanx a lot!pyrus you are great


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