A primary and a cache light

[randyrives]

I am enjoying reading this thread. Good images and intresting comments. I think radiosity can help. I used it in my daytime diningroom scene.

The first time that was flat, and boring I used radiosity only (no other lights). The second time I used additional lights to help give shape to the objects.

-Randy

[Earl]

Hi Stu,

I think you did a great job on your dining room scene. Gary, I also think you lit your teapot scene pretty good as well. Both accomplished what they set out for. And I don't think that 'spectacular' results can't be accomplished with radiosity...but I do know that a lot of people really oppose it. And that I can't figure out. Perhaps what they know of as radiosity isn't the same as what I know of as it...perhaps the programs they've played with that have radiosity, implemented it in a strange and less usable way. It's hard for me to say... but I do know that for the best quality image, radiosity really can't be beat...since it can give you the true-to-life subtly that just can't be achieved otherwise.

[s.winders]

Hi Earl [img]/infopop/emoticons/icon_smile.gif[/img]


I personally am of the opinion that I dont care what kind of lighting I use as long as it does the job [img]/infopop/emoticons/icon_smile.gif[/img] I also dont know enough yet about different kinds of lighting so I just experient over and over until I get close,then I sit back and try to work out what I have done to get close to what I am looking for.Once I have worked that out then I re tweak the lighting again and usually decide what I have just ended up with is ok [img]/infopop/emoticons/icon_smile.gif[/img]


I have also started experimenting with negative lighting as well.

Is radiosity like volumetric lighting on steroids?

Cheers

Stu.

[Earl]

Hi Stu,

Radiosity is a very general term. I'll explain how it works in LightWave, and hopefully it'll give you a good idea of how it works. Mind you, other programs may find different ways to 'fake' it. Here is the fundemental idea of radiosity:

LightWave calculates radiosity by taking the polygons that are hit with light, and projecting light from them using a semi-sphere. This semi-sphere projects the 'radiosity' light in all directions opposing the surface. That light is very faint, however, in comparison to the light that hit the surface (though, you can control the intensity of the radiosity solution). Very simply, the radiosity turns the lit polygons into miniature light sources, giving off small amounts of light (based on the intensity of the light that hits them). The result are shadows that have very subtle detail to them, which adds a whole new level of realism to the image. The details are so subtle, that you really can't add them manually - if you did, it would take so much time that you'd probably lose focus of the image as a whole.

Radiosity doesn't affect the 'theory' of lighting in any way. All it does is take your current lighting setup, and add in the details which bring the image to a new level. Take a look at this image: In it, you see a room lit by a SINGLE light source that is placed on the outside of the window. You can't really see much, since the light is outside of the scene. This is a good simulation of a daylit room. Except here, there is no radiosity to handle the subtle light bouncing.


This image, is the SAME EXACT scene, with radiosity turned on. All it does is add the sublte light bouncing from the original light that's still placed outside of the window. Incredible difference. I'd like to see someone attain this level of shading and realism without using radiosiy - it really can't be done. Oh, they also added a volumetic effect to the light - but that wasn't necessary to demonstrate the radiosity.


NOTE: Both of those images are copyright to Tor Oera. They were rendered in LightWave (no post editing in PhotoChop).

The point is...you could take your dining room scene, turn on radiosity, leave your lights as they are, and benefit from the added realism and sublte shadow detail. It doesn't matter whether the surface is shiny or rough or dull - it still applies. But again, your image looks great Stu, and so are all the images I've seen posted. Radiosity isn't a necessity - but it is an invaluable lighting tool which, if it's available to you, can add a new level of detail/realism to the scene.

[s.winders]

Thanks Earl [img]/infopop/emoticons/icon_smile.gif[/img] ...you should write a 3d how to book,you are a natural at explanations.


I havent needed Photochop since I changed my white point on my monitor [img]/infopop/emoticons/icon_smile.gif[/img]


Realistic lighting like the above image......hmmmmmm I feel a challenge coming on I think,I am gonna give it a whirl and see what I can come up with [img]/infopop/emoticons/icon_smile.gif[/img]

The scene I made above is that farm house re purposed again [img]/infopop/emoticons/icon_smile.gif[/img]


Cheers.

Stu.

[Mark (theKeeper)]

...and i LOVE that example image he posted. I've seen it before, but the mood it gives off is wonderful.

Gary... i've seen your image before also, and i love the mood of that one too. You're right i think too about the lighting having more effect than the general subject matter. And whatever rendering engine you used at the time Gary... i LIKE the effect it produced. It almost appears to be a painting, not a 3D rendering.

PS: i thought the blinds were half open myself. [img]/infopop/emoticons/icon_biggrin.gif[/img]

Stu... i've also seen YOUR image before too. hehee And i also like the "atmosphere" that is between the objects, and the viewer's eyes. You can just SEE the dust and light in the air. That's great.

PS: but make your chairs a little less tall ok? So a body's legs will fit under the table. [img]/infopop/emoticons/icon_razz.gif[/img]


I too will also have an image to post under this thread very soon. I'm just adding a few small details to the general scene and then i'll be done. It's just a learning image... nothin' to take too serious. [img]/infopop/emoticons/icon_wink.gif[/img]
You'll see...

[Gary David Bouton]

Dear Earl--(and everyone)--
one of the things I was taught in art school is to start with a general form, and then add the specifics. Failing students in college did not have the "big picture"...they labored over filagree work on a chair, when the general shape of the drawn chair looked like shit.

You're much wiser than I in the ways of today's modeling programs. I run out of date antique programs, but I still obey the physical rules of Art.

I have nothing against radiosity. What I DO commiserate about is the fact that it is generally perceived as a coool new tool ,and produces loftier results than its specular cousin, shadow and reflection tracing. Unless you FULLY understand what you are doing with radiosity, you get an unreal image. I remember when reflection tracing was "oh so cool" that everything that everyone did were shiney chrome balls.

Stu's shading is accurate in a certain sense, but it is not realistic, IMO. The shadows are way too dense for a dimly lit scene, and if there is only one light source, a dim one, you'd have crisp shadows at the base of objects, quickly diffusing out to nothingness. You'd never see the shadow of the top of the chair.

Now, as far as "Photochop" goes: gang, I've written 12 books on Adobe Photoshp (as my bio here says), and it's really not a tool to make light of.

Take a look at the attached file. The lighting sucks, but look carefully at the shadow of the lava lamp.

I painted *all* the shadows in, when I did this in 1995, because I didn't own a modeling program that would do shadow mapping.

Tools are terrific.
But ultimately the artist's eye is what determines the quality of the work.

My Best,

Gary David Bouton
Gary@GaryDavidBouton.com
Free education! The Writings Web site
and the updated GaryWorld Gallery is pretty okay, too.

[Gary David Bouton]

Would any of you folks buy a $25 US book I'd recommend? It's by Mark and Alan Watts, published in 1991. amazon.com has it at :
http://www.amazon.com/exec/obidos/AS...496974-1824660

I HIGHLY recommend this book, "Advancxed Animation and Rendering Techniques". It covers radiosity, tracing...it's funny because although it should be an "old technology" book, it covers NURBS, you name it.

I'm coming from my education from this book rather than my experience with certain 3D things sometimes, and I know there's no replacement for learning hands-on, but my head is already stuffed with Photoshop, XARA, my school taxes I must pay thin month, and fertilizing the back yard before a cold snap hits.

Seriously, this might not be the 3D user's Bible, but it's certainly one of the tablets Moses might have carried around.


My Best,

Gary David Bouton
Gary@GaryDavidBouton.com
Free education! The Writings Web site
and the updated GaryWorld Gallery is pretty okay, too.

[bmh216]

I use 3ds Max R4, and it's default renderer has no radiosity solution at all. So, for instance, if you have a single light source outside of a window, the room is pitch black. This is counter to nature. Light rays (photons) should, by their nature, enter the room and bounce around.

When I think of radiosity, I think of my bedroom, where my PC is located: most of the time, the entire room is lit by a single 100 watt bulb in an upwards-facing fixture (and the monitor itself). The light bounces from ceiling and walls to light the room, without any "super-black" corners of shadow.

Or consider the ever-popular halogen torchiere, where the light is directed almost exclusively on the ceiling: the room is still well lit, and this is the crux of radiosity. If the ceiling were black, the room would remain very dark. If it were pink, the entire room would take on a pink hue. This is not possible to render accurately without "cheating" with colored lights in 3ds.

As far as radiosity being a "new" concept, and no disrespect is meant here, it is by no means a recent consideration. I direct you here:

http://www.graphics.cornell.edu/online/box/

Check out the "history" link: as long ago as 1984 Cornell was obviously concerned with radiosity and its' solutions.

There is a tutorial supplied with 3ds Max that specifically shows you how to "cheat" a radiosity solution for the Cornell Box with colored lights. I simply prefer a natural bouncing of photons to a workaround.

(Sorry so long)...
Brett

[Earl]

Hi Gary,

I did not in any way mean to offend your use of Adobe PhotoShop. It is a very powerful program - one that has few rivals. I, though, find Corel Photo-Paint much more intuitive and useful - but by no means do I look down upon the use of PhotoShop. I find so many people say "PhotoShop" is the 'best', simply because it costs the most. The truth is, of course, both PhotoShop and Photo-Paint are top class 2d bitmap editing programs, and both produce professional results when in the right hands. For this reason, I often play around with PhotoSHOP's title to lightly express my view of how ignorant folks can see things... (no one in these forums).

So, again, I apologize for being misleading. I think it's humorous the little silent war between PhotoShop and Photo-Paint - thus, I often refer to PhotoShop as PhotoChop, or PhotoFlop, or even PhotoMop... but I do it in a light-hearted "no offense intended" sort of way. And again, I apologize for it being seen in any other light. [img]/infopop/emoticons/icon_smile.gif[/img]


Bret,

That is a perfect example of radiosity! The "ever-popular halogen torchiere"...I'll have to remember that and use it as an example for someone who's confused on the subject. Thanks!