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aurick
10-24-02, 01:30 AM
As you may or may not know, paint programs (and most 3D apps) typically use 256 values for shades from black (0,0,0) to white (255,255,255).

Nature, however, doesn't know any such limitation. There are an infinite number of natural values between black and white -- a fact that is especially visible in places where a light source exists within the scene.

Thanks to a little known setting in ZBrush 1.5, you can now give your artwork that extra "punch" that mimics natural lighting. It's found in the form of the High Dynamic Range slider near the bottom of most material modifiers.

Here's a quick example, using a space background from Photoshop. I know, it's not ZBrush. I simply chose it because it had a VERY dynamic range in its lighting -- or would if it was an actual view in space, rather than a computer-generated image.

http://www2.zbrushcentral.com/zbc_uploads/user_image-1035446850nhg.jpg

The image on the left is the image as it began. The other two used higher settings of the High Dynamic Range material slider.

Where HDR is different from simply brightening an image is that if you do that the black doesn't stay black. Instead, it brightens, too, becoming gray. With HDR values, black stays at a value of 0,0,0. However, the closer a color is to white, the more dramatically its effect is increased. As you can see, this creates truly powerful lighting effects without relying on any lights at all!

One thing that I have discovered is that it's usually best to turn the material's Ambient setting to 0. Otherwise, this is the unmodified Basic Material. It also doesn't take a very high setting to have a profound effect. In fact, the effect seems to increase exponentially the higher the HDR value gets.

And just to really show off the possibilities, I ran a test using a piece by one of the masters of natural light, Christian Lassen (www.lassenart.com (http://www.lassenart.com)) -- someone who's work I've always found very inspiring. The top half is the original painting. The bottom half uses the Basic Material with Ambient 0, HDR 2.5, a small amount of color bump and to simulate a bit of film graininess a noise value of 0.015 at a radius of 1. Notice how not only does the sky come even more vividly to life, but so does the translucency of the waves, the water glistening on the rocks in the foreground, and (thanks to the specularity and color bump) even the ocean spray.

http://www2.zbrushcentral.com/zbc_uploads/user_image-1035448162brm.jpg

Use this technique any time you have a natural light source in your ZBrush scenes to really bring them to life!

Fouad B.
10-24-02, 01:44 AM
hey !! great painting !!!!
nice colors !! :tu: :tu:

I looove transluscent effect on the top of wave

Jaycephus
10-24-02, 01:51 AM
I could see that it was making stuff brighter, and that it improved pictures with bright highlights, and I knew what Dynamic Range meant, but I didn't know how this property worked in ZBrush until now. THANKS Aurick. :tu: Now I know how to use it correctly.

DM
10-24-02, 02:00 AM
Thanks for the tips Aurick. :tu: :tu:
Dave

DeeVee
10-24-02, 06:15 AM
Thanks Aurick, I tried something like this in one of my sunsets but I did not take it as far. It is nice to know that one is moving in the right direction. :) :ex: :tu: X
EDIT: Aurick I just visited his website and his works are to say the least inspiring, I sometimes thought my colors were a bit vivid but the way he handles his colors is a revelation. Thanks again for exposing me to this great artist.
DeeVee,
Joe.

Mahlikus The Black
10-24-02, 06:28 AM
Awesome tips Aurick, Thank you!

It appears to me that this HDR is kinda like a tone curve/saturation for the image....kinda....right?
:rolleyes:

filament9
10-24-02, 07:49 AM
Excellent info aurick. that's a slider I've never really explored. I will, however, give it a try.

Flycatcher
10-24-02, 03:34 PM
Thanks for the tip, Aurick. I've used this on test images in the past when I've been trying things out, but had almost forgotten about it since and never used it in earnest. A timely reminder. :tu:

jgjones
10-26-02, 04:32 PM
Nice effect, but isn't this a bit of a misnomer? "High Dynamic Range" is used to describe image storage in which color channels have many more possible values than the standard 256 found in 24-bit RGB. This is a separate matter from changing the brightness curve of the image, or altering the gamma, which can also leave the darkest areas undisturbed, and seems to be equivalent to what is happening in the example images above. -Jim