Some help with HDRI?

[gerardo]

Yes, there are more (better) options. Take a look at this website:

http://www.hdrlabs.com/

A lot of info, techniques, (free) HDR tools, news and a very useful book :)




Gerardo

[locke2121]

THANK YOU! The problem is EVERYONE talks about HDRI...but comparativly few people KNOW what they're doing. At least know enough to teach others. Right now I'm struggling with the combination of several images at different exposures into a single HDRI and I'm not doing something right...I just get a washed out image. If I had CS I could do it with the built in tools but I just have PS7 so I'm a bit behind the times.

Any more help and I would be grateful!

[gerardo]

In that case you might want to get Blochi's book. It's really cheap considering its useful content. Btw, have you checked the above website attentively? The answer of the problem you mention is right there.

About your wash out result, it's hard to say without knowing what you are doing, but in HDRShop the problem could be an improper camera response curve (or generic gamma if you are not generating a camera curve) or even wrongly preset scale increments.

Picturenaut could be easier for you since it can self-calibrate each set of images on the fly and it's free, besides it has many other nicities for CG and photography that you can check in the above website.



Gerardo

[locke2121]

There are some sweet little programs there! I'm still a bit frustrated...I always am when I start a new project or facet of learning. :) As for the book, that'll have to wait till i gots more money! But it definatly a future read! Thanks for the help....oh, I haven't seem to have found the exact answer to this yet...but what is the difference between a HDRI and a Light Probe???? Carrara uses HDRI...but Bryce uses Light Probes...these are my two main renderers right now.....and I'm not sure of the difference. I can turn a HDRI into a light probe with HDRShop...but I gather HDRI's are used more often that light probes???

[noouch]

An HDRI is just an image with a high dynamic range, normally in the form of floating point pixel data. A light probe is a 360 degree HDRI taken from a central point containing information about the incoming light around it, hence the name.

[gerardo]

Yep. As Noouch has point it out, HDRI states for High Dynamic Range Images, however some people say Imaging and not images. In the first case they are basically images that can store the full lighting range of a scene (more than 23 EVs) and can hold 32-bpc (bits per channel) and they indefectibly need floating point pixel data (there are Medium Dynamic Range images which don't). In the second case (understanding as imaging), it refers to the methods and toolsets for creating, capture, store, edit and process images with these high contrast ratios of light.

A lightprobe on the other hand is a coordinate projection format, well-known also as angular map. It contains a full panorama, and do notice that commonly in these days, almost any type of HDR image that contains a 360°/360° panorama is called lightprobe (even when they use other type of projection).



Gerardo

[locke2121]

So basiclly a light probe is a wrap-around panorama that has been stiched together? you gotta understand, I can MAKE a light probe...but I somehow missed out on exactly what I'm doing lol! Sorta like putting someone at the controls of a runaway train and telling them to run the train or die.

[noouch]

Can you post the HDRI you created? It might give us some insight as to what's going wrong.

[locke2121]

Actually everyone has already helped me learn a few new things...perhaps one of my biggest mistakes was using low-bit jpegs instead of high-bit tiffs! I've seen a decent increase in results just by changing that! I also need to upgrade my camera equipment. I also found Photomatix which REALLY helps me in combining images! Just be patient with me...I'm not the smartest tack in the drawer sometimes. lol

[locke2121]

I also think I need to move away a bit from Bryce and use Carrara more. I've always loved the ease of Bryce and I've gotten decent results...but its Sky Lab isn't detailed enough for the kind of light control I'm looking for. I've got C5 and haven't really used it much...the step up in complexity from Bryce sort of steered me away...but the more I play, the more realistic results I get.

Also Carrara can use straight HDRI's..where as Bryce needs them to be converted into angular light maps...one more step I don't have to worry about.

[locke2121]

I think I'm getting better. Here are two pictures I've done with a new HDRI I made from a picture of an abandoned factory. I still don't have a good digital camera so i've sort of faked different exposures and combined them in Photomatix. I'm sure photos with real exposure differences would be better...but for now I'm improving. One is a straight HDRI render, the other has a weak key and fill light setup to add some shadows.

On that note let me say thank you Jeremy Birn! Your Lighting and Texture books are two of my best texts!

I still have questions I've yet to answer....like why some HDRIs seem to be a full mirror globe with the camera in the center, while mine aren't.....they both seem to be latitude/longitude HDRIs....they just don't seem to act the same.

But I'll find my answers...expect more questions from me...like I said I can be a little slow when learning new things on my own....but you guys are GREAT! I don't think I would have gotten this far without all the help!

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