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19.04.2024, 03:04

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Eden "Paradise Lost"

Eden "Paradise Lost"
Description:	This is my eigth project using Bryce5. I think the sky came out pretty cool. I just filled in the rest afterwards.
Added by:	tina gazcon
Keywords:	Bryce, 5, Paint
Date:	11.28.2006 00:10
Hits:	3726
Downloads:	91
Rating:	0.00 (0 Vote(s))
File size:	33.1 KB

Previous image: REVISED A Bug and a Brook

Next image: Arctic Camp

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rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2610

use this scene to learn about secondary lighting!

Yes, this sky does have something to offer.

I have alot to say this time so please bear with me.

I will explain in detail a few things as you are not the only person who needs to read what I am writing.

In a scene like this shadow corrections are a paramount concern. Shadow corrections are always a paramount concern actually. You have done well with ambient and skydome, but if you want realsim then an entirely new appraoch to lighting will be necessary.

This particular scene itself I feel could be an ideal place for you to start experimenting with secondary lighting as David mentioned in the other scene (sanctuary). I thought it was too soon to bomard you with this, but maybe it's not since you say you want big time realism. The above scene is simple in composition compared to the other one, making it easier to edit and to experiment with. The back-lit nature of it means it is the perfect place to use these shadow correction ideas, more so than the other one (Sanctuary) which is lit in front with few visible shadows. You want to know what the big boys know and render realism with ease? Lighting is 95% of the work. Learn this and you will know pretty much all you need. Like they say about learning to say please and thankyou as a kid sets one up for a good life. It takes most people years before they come to understand this stuff. It's so simple, people just don't notice that it's necessary. They fall for the ambient channel trap because the stupid bryce preset libraries assign an averare of 19% ambient to everything, even stone, wood, and metal! People assume this must be okay since the program designers did it. They are wrong. Accepting this flawed reasoning, people assume that everyday objects need ambient channel expression to look realistic in 3d renderings, and they don't. Brycer's often render "cartoons" that they think look like real photos. They are deceived. They are too engrossed to see the obvious failing of their ambient channel glowing materials. The ambient channel is 2d, making all it touches a bit cartoonish. The more ambient, the more flat and 2d cartooninsh the texture. Real life is 3d. So is secondary lighting. For realism, you will use no ambient channel expression in your materials or sky dome expression in your skies 99% of the time!

Here's the skinny:
Bryce is a brilliant program. It does alot of very realistic things for you. But it does not have global illumination. GI, is the general term for the true cause and effect "bouncing" of light that occurs in nature. It has many consequences including causing a lightening and softening of shadows in the real world. Think about that for a second. Bryce, as much as I love it, only calculates direct lighting values and light passing through transparent surfaces. That's a good start, but there's alot more. Bryce does not however, calculate how light changes COLOR and lowers in INTENSITY as it "bounces" off of one surface onto another surface within a scene, better known as indirect lighting. This is a very big deal. Light does not bounce in Bryce! Crude Example: If you place a mirror in a bryce scene and shine a bright light beam (spotlight, not radial) onto it, the light should bounce off the mirror and onto other objects in the scene. The curve of the mirror would determine where the light fell, as it was bouncing off the mirror surface. But it doesn't work like it should in bryce. All bryce will do in this situation is create a bit of a bright spot on the mirror where the light hits it, but the render engine will not calculate where the light goes from there. Meaning the rest of the scene will not receive the illumination that bounces off the mirror and will remain dark. Like boys do to girls in school with reflective surfaces such as flashing her face with the sunlight bouncing off of his shiny watch to get her attention. In Bryce, the girl's face never receives the light, so he gets no date! This is a huge failing in the way of realism, and reproduction (just joking). Bryce will "reflect" the IMAGE of something, but it will not actually "bounce" the light within a scene.

Light radiates from it's source, hits the air (bounce 1), then strikes an object (bounce 2), then it bounces around striking other objects, until it is absorbed either by more objects or by the eye of a person looking on. By the time we "see" a photon in nature, it may have bounced a seemingly infinite number of times. Each time the photon stikes an object it loses energy, reflecting or bouncing the left over energy as light of a particular color. The equations needed to calculate the behavior of light bouncing between surfaces within a scene are well known. They are large equations that take a long time to calculate or render. Almost no one has the time to sit around and wait for a computer to truly calculate this bouncing. Light that has bounced off of a surface before hitting the eye is known as indirect light, as it has been changed in some way since it's creation due to interactions with nature.

That's where the ambient channel comes in. Bryce provides you with the ambient channel because it knows it cannot calculate the indirect light that should be there to lighten the intensity of the shadows. The problem is that the ambient channel must be "tuned" by you. As in you yourself are expected to calculate the amount of left-over indirect light that should be there to strike the object from behind and from the sides. It is almost impossible for a human being to do that accurately, especially in a scene with alot of different materials. Even assigning a consistent ambient level to all textures in the scene will not work. I say this because people think that will work and they are dead wrong. Usually, ambient expression is way way overdone! I can almost ALWAYS tell when there is ambient in an image. As things glow without reason because the artist wants things to be "seen." The skydome is Bryce's attempt at providing the light that has bounced around in the atmosphere before reaching the objects within the scene. The sky dome is a great tool and was the original "secondary light." the problem with that is that it provides illumnation from exactly 90degrees above, no matter where the sun is placed. It is also a bit flat in that it paints it's color onto the objects in the scene. Even indoors a skydome will effect the objects, as skydome casts no shadows so it's illumnation penetrates everything. The real problem is that when light bounces in the atmosphere it's the illumination from the sides and from behind that we miss much more than from above. This is why the skydome is ultimately useless in my opinion and needs replacing, with secondaries that are better placed.

This then brings us to seconary light sources. In nature the light fom the sun would bounce around in the atmosphere and strike objects from the side and back, all in relation to the direction and intensity of the primary light source. Basically, if you have a primary source at north at strengh 10 at full white, then at east, and west you want weaker light sources at strength 1 with a gray color and no shadows cast. In the position of south, you woudl use an even weaker light of strength 1 but very dark gray. this will create a gradient that follows more naturaly the bouncing of the primary light within the scene.

I will e-mail you with more specific ideas, but I wrote this whole big thing out here so that all can appreciate what we mean by 'secondary light." Secondary, as in to mimic the indirect light.

You will hear from me soon. Til later.

11.28.2006 05:47

Nightst4r
Admin

Join Date: 12.11.2003
Comments: 451

Comment

That was a fantastic comment. Very detailed and really gets into the gritties about ray tracing and what not. In the spirit of noticing it was way too small to comphortably read... I've taken the liberty of increasing ALL comment sections to size 14px Arial font. Hope that helps everyone.

11.28.2006 06:28

rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2610

thanks nightst4r

I knew it was long but not this long. I'm a bit embarrased I wrote that much so thank you for not scolding me for it's length. I hope people find it useful. The larger font size will be nice for our eyes. thanks.

11.28.2006 06:51

tina gazcon
Member

Join Date: 08.07.2006
Comments: 254

Thankyou!

You guys are GREAT! I had to laugh out loud at Nightst4r comment and your reply. I truely appreciate your advice and am putting it to use right now. Im redoing Santurary and will redo Eden when Im finished. I get it now. Wow what a difference it has made. Im glad you and David finally told me. I was wondering why my work looked like paintings. Ha!Ha! I'll resubmit them when I'm finished. Thankyou all again.

11.28.2006 17:06

Horo
Admin

Join Date: 05.26.2004
Comments: 4721

Font Size

Thanks Nightst4r. The larger font works on MSIE but does not on Firefox. Here, it is unchanged. However, nothing to worry about.

11.29.2006 14:04

Nightst4r
Admin

Join Date: 12.11.2003
Comments: 451

Really

I opened it w/ the firefox I have (1.5.0.8) and it does look bigger. I'm comparing it against lets say the size of the text in the Description of the image per say? Are you seeing them the same size?

Tina, don't be afriad to render to a higher quality and bigger JPEG. 33k is pretty compressed and to really shine its nice to have an image thats around 200 - 300k. :)

12.02.2006 06:47

davidbrinnen
Admin

Join Date: 01.03.2004
Comments: 2224

I have often wondered...

Why when bryce can do the reflection of an object in a mirror does it not go one step further and simulate the reflection of a light source?

All you have said Rashad, I agree with, however, for myself, I prefer the look of secondary lighting with the ability to cast shadows. It is a subtle difference and it does take longer to render out, but it prevents the secondary lightings effect from becoming too uniform in the final image. Also, when dim secondary lights are employed within a scene that cast shadows, then more might be needed in scene to get the desired level of lighting.

Still you have made a lot of good points well and I hope more people read your comment and appreciate the value of your advice.

12.03.2006 12:39

rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2610

Yes David, in some circumstances you may want your secondaries to cast shadows, it all depends. Is the scene indoor, outdoor, or some combination of the two? Indoor secondaries will have limits or fall-offs, wheras outdoor secondaries for scenes like Tropical Island Sky have no fall-off. I was mimicing atmospheric bouncing so I need global effects, not local effects. The greater the open sky, the more likely you want secondaries with no falloff an no shadows. Indoors you need fall and sometimes shadows, depending. Overhead canopy can be considered indoor if it block most sunlight fom above and the camera is placed below.

12.03.2006 16:20

caperh
Member

Join Date: 05.24.2004
Comments: 262

I like this project realy nice, I think this is one of your best projects, keep going.

05.27.2007 20:46

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