I've been reading about Vue 5 and what it can do with HDRI images in terms of matching the lighting of the scene to that of the image. This all sounds very exciting but the one thing no one says is what exactly is a HDRI image and how is it different from any other kind of image ? Is it something I can create with just a regular camera ? Is there a good place to shop for these images online and can I find more variety of these then just ones of skys ? Hoping somebody here and demystify the process! :) Thanks!

Vue 5I can make .hdr images for other programs to use including it self. If you want to buy some you could go to www.doschdesign.com.

Search the net there are lots of free samples out there.

Regular image files are encoded in 8 bits, HDR files are in 16bits minimum, up to 96 bits. They store precise lighting information,  as well as different ranges of exposure. Dennis gave you the right info to buy some, but they don't come cheap. lots of free ones on the web, including here  (skies only, sorry!): evermotion.org

Try this link to better understand HDRI imaging:

debevec.org

Not sure if i'm right about this but hdr was developed for motion pictures as a cheaper way of intergrating 3d into their movie scenes, because hdr holds the light information in a file you wouldn't need to setup the lights manualy thus being able to spend more time on animation and less in scene setup.

The rest of us use it to get a sharper lighting effect on our models/scenes.

Image Based Lighting (IBL) is another great way to light a scene this is were you use a picture file to light you scene, not as good as hdr but still very effective.

I've got a few skies made with Infinite for sale in the marketplace ;)

Point is, since .hdr files are High Dynamic Range, they contain true brightness values of an image, not just the colours. Thus they can be used as a light SOURCE.

ie, if a patch of sky has a brightness of say 1,000 and the area near sun has 32,000, and an area of cloud is 400, all those light areas are prjected down onto the model area, as real sky does, thus giving true lighing.

http://www.renderosity.com/viewed.ez?galleryid=1211952&Start=1&Artist=silverblade33&ByArtist=Yes

that was made using an hdr I made of the scene's actual sky, then reimport the hdr, use that for lighting, I find it gives better, faster effect than rendering with GI

:)

Exactly! HDRI is 'High Dynamic Range Image', meaning it can record scenes with a much greater range of brightness than any previous recording medium, such as photo film. Ansel Adams would be delighted - no need for his Zone System.

In fact, if display monitors were as good as they should be, an Image Based Lighting (IBL) scene (one based on an HDRI image as the light source) of a bright sunny day, where you can see the sun, would throw a beam of sunlight out and illuminate your room.

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Silverblade, how do you make HDR images in Vue? HDR images are a  collection of the same picture taken at different times of day or at different exposures to store all lighting info in one file. Can you do this in Vue?

In Vue, set up your scene and atmosphere.  Then from the menu, select File>Export sky.  Select .hdr and away you go.  Just learned this myself not that long ago. 

Lin

Yeah, I know that, but technically speaking, I'm not sure the resulting file will be true HDR, since HDR files store lighting information taken at different exposures or different moments of the day.

Bruno, My understanding from the debevec.org site was that they aren't taken at different exposures at different moments of the day and combined as a single HDR image.  The are a highly detailed info-laden panaramic photo taken from one spot at a single point in time.  The way some take it is by pointing their camera at a mirrored ball on a tripod.  Then going to the other side of the ball and taking another photo then stiching the two together in a special (freely available on the web) program that makes a single HDRI image which appears like a warped sphere.... but when it's reflected on your object or windows in your scene looks scary-realistic.  It doesn't carry multiple times of day in the same HDR image.

Hmm, I'll have to get another look at the site. Thanks FuzzyVision.

Ok how I export HDR is this, in Infinite:

File-->Export Sky

select UV SPHERE, and set the size to 3000 pixels or so, if you want a CLEAR background image. If you don't need a clear image, ie, say use depth of focus so background is ok to be blurry, or not even seen, 1000 or more will do.

makes aweosme pictures because it lights the scene exaclty as a the REAL sky does. The rela sky throws ligth down form all angle,s but in varying degress, that's why you never see a totally black shadow in real life outdoors.

 http://www.renderosity.com/viewed.ez?galleryid=1211952&Start=1&Artist=silverblade33&ByArtist=Yes

I did that using an HDR of the scene's own sky ;)

Bruno

not exaclty..that's how currently we have to take HDR pictures, because there is no camera film (or card) that can create ro store HDR images. See, the problem is, film (or digital media) only records COLOURS, it doesn't record true LIGHT OUTPUT, which is what HDRs do. TO simulate that, folkt ak emultiple exposures, and combine into an HDR on a computer. One day there iwll be hdr media, and so camera will be able to make hrd directly

:)

So, Silverblade, you mean that when you output a Vue render to HDR, it does store all of the sunlight info? But if you change the exposure and contrast values in the atmo tab, will the lighting taken from the HDR file still be accurate?

For more of information, you can be going to see also to this address : http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm

Imagine an HDR as basically a gigantic torch, in colour sourrounding a scene and beaming down onto it, exaclty liek a real sky or surrounding does. brick walls reflect light for example.

in Infinite you can chnage exposure contrast, this alters the light output from the HDR :)

normally it's set to a neutral 0.0 baseline.

There are some free HDRI images from three different companies in the newest 3D World magazine.

Now I have the 3D World in my hand its issue 79 (July 2006) in case anyone wanted to know.