Why is it that all Vue textures start out with a 40% Ambience? This makes it look a little cartoony for my taste and I can't figure out why it's the default. Which brings me to this question - is there a way for me to set preferences that EVERY texture I pull or make would come up with 0% Ambience. Right now I open a texture I wanna use, change it to 0% Ambience (as well as any other tweaking I'm going to do to it), and re-save it in my personal folder at that setting. Is that all I can do, or is there a way to automate the Ambience? And I really don't want this to turn into a bashing session about problems and bugs - just looking for general information about this subject. Thoughts? -Lew ;-)

Sorry, don't know any way to do that, unless a Python script could work - have no idea if that's possible.

I can think of several good reasons why ambient and diffuse are set 20 apart though. Like to keep people from making dead black shadows by default, because of the drastically limited dynamic range of monitors (maybe 100:1, compared to human vision of 30,000:1). Or the fact that radiosity rendering needs lots of ambient.

Like you, i usually tweak those setting or change the contrast slider. Being able to change all materials in one setting would be very handy. Let's request a feature at e-on's web site (the more who do, the more likely it'sll happen).

e-on feedback center

_jc
Art Head Start.com
Art training e-book for digital artists and students. Free chapter on lighting.

I used to change all materials lighting to 80/20, but this was so tedious! Now what I do, is change this ratio in the atmosphere tab, and set light balance and ambiant light to at least 60% towards sunlight. I think it gives good results.

This setting is also one that has a big effect on the "graininess" you get with some renders of some scenes. Less ambient usually means less grain. However other fixes are often needed too. And for radiosity, you do need lots of ambient to reflect around your scene. If you're doing commercial work against a budget and a deadline, mass changes help. If you're trying to make the best image you can, than adjusting each material independently makes sense to me.

To me, the fact that radiosity requires MORE ambient light makes no sense to me. Now, if I understand correctly, it calculates bounced light. So direct light should be bouncing and illuminating surfaces not facing the sun. Is ambient light not just a standard uniform brightness? Thusly, with more ambient light, wouldn't that lighten the dark areas uniformally? I ask cause it seems to be the exact OPPOSITE of MicroStation rendering.

My understanding is that ambient light is FAKED (in the absence of Radiosity calculations) by adding a uniform light level everywhere. But this is unrealistic.

In the real world, ambient light (just like ambient audio noise) is caused by direct light being reflected around the environment (becoming "indirect light" = "ambient light"). One of the main purposes of the Radiosity method is to accurately simulate the ambient light in the scene that is missed by other methods (e.g. ray-tracing, etc.). Radiosity does this by dealing with light as power, instead of as rays. So, with Radiosity, there is no need to add a uniform light level to scenes to fake the ambient light level.

Since the indirectly reflected light power calculated by Radiosity IS ambient light, more ambient light level = more Radiosity effect. In other words, what we call "ambient light" is just the sum total of all secondary, and higher order, reflections of light in the scene. Crank up the ambient and you increase the intensity of the reflections.

Make sense?

_jc
Art Head Start.com
Art training e-book for digital artists and students. Free chapter on lighting.

Message edited on: 01/09/2006 14:03

Thank you for that breakdown! So true ambient is off until we hit Radiosity...it's faked in General, GA, and GI? So in essense it IS like MicroStation rendering. Ambient is faked until you hit Particle Tracing rendering method (aka Radiosity).

Yep :o) And faking ambient by adding one level of light energy to the whole scene is not only unrealistic, it further lowers the dynamic range of your scene (less contrast and a less "crisp" look).

It's like trying to fake the ambient noise, in say a restaurant, by adding pink noise ("pink noise" is random noise, like "white noise", but with low frequencies emphasized to follow the human hearing curve). That pink noise is going to make it harder to hear low level conversations - lower dynamic range. And it's not going to sound like people talking, eating utensils clanking, etc. So it's an unrealistic simulation of real ambient noise.

Message edited on: 01/09/2006 14:35

Okay, so no general fix - just keep doing what I've been doing. And JC - thanks for all the info - didn't realize that about the Ambient levels with Radiosity! I have some experimenting to do now! -Lew ;-)