Attached Link: http://www.bsmooth.de/BSolutions/#TerrainEditor

I was looking through some of the forum messages and I was pointed at the link attached. Basically I've always tried to make shadow and light behave differently on textures than what Bryce does. I wanted a bit of graininess, a bit of realism, like you can see sometimes in Cinema 4D, 3DS Max or Maya. Let me know what you guys think of it. drac

well, the first thing I notice is the space under the bowl. It should be darker right under it, then gradually getting less dark as you move away. It's a detail that can turn an unreal scene into a realistic one. In my opinion Bryce soft shadows and indirect lighting do not measure up to its superb rendering engine.

the light comes from the camera, more or less. and it's the sun, mind you. there's also a small light on top of the vase :)

What you're describing is just the nature of Bryces shadows. Bryce (and other 3D apps) cannot produce shadows that are dark at the base and lighter as it travels out and away. So, it's not really anything draculaz missed, it's just that it can't always be done. (But, hopefully will one day be fixed by Corel) draculaz, this came out well with the textures. They're color spreads out great with that soft almost powder-look to them. Cool little ball-object. AgentSmith

If any of you want the models (the vase is actually pretty good), I could always upload them in the freebies section :)

Actually true radiosity doesn't work that way, an object will reflect a lighter light from it's base before the dark part of the shadow starts, the reason being it's the closet part of the object to the surface, therefore it would actually project it's color there first "over-shadowing" shadow, it's a natural trick of light. So Even Maya or Lw, Cinema etc can't make it right because it's a true phenom. There's an article on light study about this if I can dig it out I'll post the URL.

Yeah, another attribute of radiosity is exactly what clay is describing there. Imagine a bright yellow ball on a white matt surface. With enough area light the yellow of the ball would actually be projected onto the white surface. (to a certain extent, around the base of the ball)

Yes, I would love to have you objects!

Agent Smith, perhaps the shadow could be faked with a ranged negative light, or an inverted (and properly elongated) bowl? Just a thought or two. clay and all, There are whole books written on radiosity. I think I have one in PDF I got with the Graphics Gems I-III CD. At the time, several yearons ago, I didn't understand what they were getting at - althought Peter Sharpe's tutorial on the subject helped me understand how to do it, I'm still not sure what it is although clay's explaination helped a little. looking forward to the article, - TJ BTW Frank Sinatra's BD today. 1915-1998 also Edward G Robinson (info from KMJ AM radio station here in Fresberg.)

Agent Smith, (X-thread) So Radiosity is when the color of an object is transfered to it's shadow ? I've seen that in real life many times and always that it was a neat effect never knew what to call it. -TJ

The best way to see how radiosity works, set up a similar object you are building in real life and just study it, adjust your light source(s) to what you want and just study how the object interacts with its surroundings. I think that's about the best way to to explain it and experience it, after all, it's a constant that's around in everything.

clay, I reread the first chapter of Cohen , and I think I derived a working definition, perhaps incomplete or partially incorrect: When a light strikes an object the reflected light carries with it some of the color of the object it reflects off of - in addition the light has it's own color. these colors in combination will be imparted to any other object the light strikes. It is not just that - particles in the air (having their own color will add to the blend and the visable light produced from that. they quote Renoir as saying that Shadows are never black(hey I knew that) and imply that radiosity applies to shadows as well. further any mirrored surfaces are included in the definition, so I can see how refraction and relection play into the HDRI and how that relates to radiosity. It is then a catch all phrase, the grand unification theory of the art world ? Clay, now that I (think I) know what to look for I can take your advise, but correcting any errors and ommissions I made would be helpful. - TJ

Yellow tennis ball, kitchen counter, morning sunlight. Study, real life. It's the best way. And, the cheapest, lol.

Some 2d artists use the complement of the color of the sunlight for shadows. Painters have been working with light for years. Looking at a few paintings would help too.

This is a straight bryce render, top and bottom. The only difference between them is blurry reflections. If you set the ground plane to 40% reflective with a specular halo of pure white, then place, say, a red ball over it, you will get the illusion of the reflected light. It works out well because blurry reflections have falloff based on the specular halo whiteness value. Therefore, a material with the specular halo set to white will only mildly reflect whatever is right next to it.

Agent Smith, Cloudy today - might rain. So I'll have to substitute a watt or two. Right now I wish I had one of those lamps with a dimmer knob. madmax, You're on to something with the reflections. I can see how that works. Thanks, - TJ

I have found that most people tend to use the softshadow options set too high. At the lower values for individual light sources, I find i can get sharp shadows close fading to soft as distance from casting object increases. try experimenting with lower values.

Darc, I like the objects in your pic too! The spikey little ball thing and vase are very good!

Incarnadine, I've been playing around with that and must admit I don't know much about that yet but from what I've seen so far it appears to be as you say. In my post 2 posts above the explaination given is that one given by Cohen et al a few years ago (in my own words of course) - so it is the shadow and the reflection and the blended color and the hazeyness of the air and visable light and HDRI and some other stuff I don't know to include yet. On HDRI which I see as part of radiosity: Taking an example of a tumbler shaped glass (cone pointed downward) and a viewpoint at or above the glass, I noted that What we're calling HDRI should reflect what is in front of and BELOW the glass.(I noticed that the image doubled vertically - can't explain that yet.) at the base of the glass (because it is solid it reflected what was BEHIND the glass) (Angle of incedence = angle of coincedence. ???) Believe it or not I couldn't find a colored ball or any sun light today (Tule Fog,) so that experiment is on hold, but I'm gonna look at a spherical, reflective Christmas ornament next. That Should be fun. oops - in my excitement I forgot to compliment draculaz on the vase and lighting. Very Good. - I seem to remember several years ago, Jody telling me that a vase should not be too thin, because it becomes too hard to fire without cracking - but then at that time she was only beginning pottery so I am not sure about this(?) - TJ

Hmm, I put a camera above a upside-down cone and it seemd to look as I thought it would. It distorted the view directly below it and slightly reflected what was around its sides.

Agent Smith,

Note the red in the left hand glass refracted from the nearer red cylinder and the torus reflected in the right hand tunbler. im real life the torus is repeated higher and at a different angle. this was done on Bryce 3d as I accidently chose it rather than B5.

anyway that's similar to what I saw in real life this morning except for the yellow haze.

If the glass were a cylinder I imagine The reflection of the torus would be different and different still for a sphere, but incidence seems to equal coincidence.

• TJ

Here's an image of internal refraction. Bikermouse! You need watrer in those glasses! The water should have a different refraction as wel, for then you get intersecting crtitical angles, which gives you the nce reflection vs. transparency. If you make them right, like in a nicely cut diamond, the refraction will produce it's own reflective images, even thoguh there is no reflection on the material itself. See my previous post with that cornell box image and look at the glass sphere. There is some blue in it on the right side of the sphere, but it has no reflectivity. It is purely the refraction along with TIR that creates the illusion of the reflected image. Half of the light is reflected back into the sphere, while half of it leaves and hits your eye. there is an angle for each material that represents the cutoff of this effect, called the critical angle. If anything strikes shallower than the critical angle, it will be reflected back. You can see this if you look at the water from the bottom of a swimming pool. You can only see the outside of the water in a certain zone of vision (which happens to be circular) and outside that zone you are looking at the reflection of the bottom of the pool.

In this example, the emerging rays would be what you see as the bottom of the glass repated, and the reflected rays are what make up the other crud. That is why you can only see part of the bottom repeated toward the top. As refraction increases, so does the critical angle. So in a diamond, i can see more of the bottom than if it were made of glass.

Sooo....the problem with bryce, and it;s the only major optics problem is that BRYCE DOES NOT REFLECT VISIBLE LGHT RAYS!!!!! That's why we have no radiosity and that's why you can't see the proper refraction in a glass of water. Try it. Make a cube and apply a mirrored material. Add a pointing at it and render. You'll notice that there's no light on the ground that's reflected from the cube. WE NEED THIS!!!! If bryce had this, then radiosity would be no problem, because it IS the fundamental componet of radiosity that is not in the realm of shadowing. It is responsible for anisotropic reflections, brushed metals, and specular flares.

I recall that water is 1.3 (about) and glass is 1.6 (about) air is (about) 1.0. Starting to sound like Snell's Law - wish I could find my optical mineralogy book. I left the water out as I was interested in the glass (and I didn't think of it)- besides this was a "quick" render done in about 20 minutes (or it would hsve been if I hadn't had to do everything twice.) In 3.1 couldn't set TIR - I am chafing at the bit to try TIR. Perhaps on the weekend - TJ

Bikermouse, you can make the double reflection in bryce. Just add water to those cups. If there is no water, then the light is refracted by the first glas layer, but then refracted back to normal by the second layer. The water refracts it even more, and then the second wall takes a little bit away. You can see why this stuff can take a while to render...hehhe

Ok i;m done...phew!

Yeah, TIR will help a bit with all this. But, then you realize as madmax does, Bryce cannot reflect visable light rays, and yup, that's what radiosity is. TIR helps with the inner reflections, but what is also needed is outer (light) reflections/bounces. AS

Good example madmax. Bryce also needs caustics. (thought I'd throw that in there)

Agent Smith, Ah, visable(external)reflection of light. Thank you. so what your saying is that it does visable light alright but not visable reflection of light. got it - I think. ok i'll bite - caustics? - TJ

You got it. Caustics - The enveloping surface formed by light rays reflecting or refracting from a curved surface, especially one with spherical aberration.

Caustics are the warping of light you see at the bottom of a pool or that you stereotypically see on the backs of dolphins as they swim under water, etc.

Photo example.

Agent Smith, Thanks for spending the time explaining all of this - I'll try to finish up in the morning. must sleep been up 46 hours trying to get these facts into my head. again thanks, -TJ

Lol, try not to dream of radiosity

Air (STP) 1.00029 Amethyst (Quartz) 1.54 (+1.55) Beryl (Emerald) 1.57 (+1.60) Citrine 1.55 Corundum (Ruby, Sapphire) 1.76 (+1.77) Emerald (Beryl) 1.57 (+1.60) Diamond 2.417 Garnet (Pyropes) 1.73-1.75 Garnet (Almandine) 1.76-1.83 Garnet (Rhodolite) 1.76 Glass 1.517 Peridot (Olivine) 1.65 (+1.69) Quartz 1.54 (+1.55) Rock Crystal (Quartz) 1.54 (+1.55) Ruby (Corundum) 1.76 (+1.77) Sapphire (Corundum) 1.76 (+1.77) Topaz 1.61 (+1.62) Tourmaline 1.62 (+1.64) Vacuum 1.00000 Water 1.333 High' Zircon 1.96 (+2.01) Thought maybe these would be handy here.... :P This is a very informative thread! TMGraphics

What are these?

Agent Smith, Thanks I didn't even dream that I remember, You will find the refactive indices of minerals such as these in most books on mineralogy - Dana's Mineralogy is pretty much the standard. The refractions used in Bryce pretty much match the actual real world indces of minerals. I recognise some of them but it's been a long time since I majored in Geology so I can't vouch for the indices listed by TMG from memory. - TJ

Okay, but the refraction levels in Bryce are between 0-100. How do I relate this to those numbers above?

Agent Smith, It goes to 300 in the material lab. - TJ

A lot of labrotory geology has (or had - methods may have changed drastically in the last few years) to do with looking at rocks glued to slides and ground to a specific thickness so that they can be viewed in microscopes specially designed to work with indices of refraction - did a lot of this type of thing in my school daze. snd so was one of the first things I picked up on in Bryce. Unfortionallybecause of my background I keep trying to approach art from a scientific point of view it seldom works - but this may - with translucent or transparent objects. - TJ

Lol...I know. How does the number for say; Air (STP) 1.00029 Fit into 0-100? How is one supposed to use the above table for use directly in Bryce?

Agent Smith, Oh I see: multiply the actual number by 100 so 1.00029 becomes 100.029 or 100.03(rounded up) sorry about that - I convert the figures automatically in my head so I didn't understand the question. - TJ

Lol, I don't think anybody else does (automatically), so thanks, I understand how to use the info now!

No, I think oddly I Think - Just a way of saving time I've trained myself to use so I can estimate quickly rather than actually doing mathmatical calculations.

Ill have to remember that refraction calculation for Bryce, thanks! What is weird to me, is that I used a refraction of 1.333 for the glass in this picture, and not 133.3. TMG

It'll be a while before I get this light stuff down = Oh well.

TMG,
Must experiment with this. 1.333 not 133.333 ?
According to the manual IR only works in B5 at values
over 100. bikermouse scratches head(???)

Something I hadn't thought of in terms of global warming -

salt water apparently has a different IR than fresh water - the IR can, at more obtuse angles determine if light bounces back or is absorbed by the object at the INTERFACE between the two objects - the IR of fresh water is enough differnt from that of salt water that it allows rays (and heat energy) to be absorbed by the water rather than bounce off - the inference is that this contributing factor to globasl warming (real world example.)

so IR could effect the reflective quality of a material -
perhaps the reflected color as well.

Madmax,

I do thank you for the time and effort that you put into this thread as It has been thirty years since I was in school and the review is, to say the least, timely.

Although your example was very good, the doubling effect you mentioned earlier wasn't what I was talking about regarding my observation of reflection off of an empty glass tumbler.

My concern was about a reflection being repeated on the OUTSIDE surface of an empty glass vertically. From what I could tell this is solely an external reflective quality, not an internal or refractive one. It may be the poor quality of the glass or some aspect of the reflective quality of aluminum, but odd as it sounds - two external reflections sepatate and "tiled" vertically.

I guess as it stands it's still just a wierd observation
poorly described my me.

• TJ

@BikerMouse - I went and checked my project file on the above picture - and I stand corrected, it was a setting of 133 not 1.33 :> Sorry for the confusion! (searches for lost bottle of GinkoBiloba) TMG