Help with Architectural Radiosity?

[Cinema1954]

Don't know if this addresses your specific questions, but there's a great analysis of radiosity settings at this URL: http://www.mvpny.com/RadTutMV/RadiosityTut1MV.html

[amapimaster]

Hi

I know the problems your facing! Do you need to have both the interior and exterior lit well at the same time? Or can you light the visual twice if you know what i mean - once for exterior shots, then again for interior?

I cheat sometimes by removing walls that you cant see from the current camera angle - this seems to let more light in.

Post a pic if you can!

[AdamT]

You know, there's no law against putting a low-intensity omni in the middle of the room to brighten it up. I know it's tempting to want everything to render the way it *should* render automatically, but sometimes it's impossible or more trouble than it's worth.

[say-g]

You know, there's no law against putting a low-intensity omni in the middle of the room to brighten it up. I know it's tempting to want everything to render the way it *should* render automatically, but sometimes it's impossible or more trouble than it's worth.

some wise words there, alas i learnt the hard way

[Mike Hooma]

yeah it was inside and outside by same lighting, I guess whatever makes it works is my new philosophy :)

[FusionDG]

Hi Mike,

I do architectural rendering also and have been running into the same probs. :argh:

It’s good to see others having the same issues [misery loves company :D ], and what Adam says I guess is what I’m starting to lean to also.

Like you say, whatever it takes, the homeowner doesn’t know! Between the client and myself, I seem to be the only one who has an issue with the lighting “integrity” of the scene, so I might as well plop that omni in to get the scene brightened up.

[MJV]

The thing you need to remember is to not put the light in a place where it couldn't physically exist without being seen. This is just about the worst mistake you can make, imo, and a too common one at that. If you just plop a light in the middle of the room, then your render is going to show physically impossible lighting. If you need extra light, place it behind or out of site of the camera and reflections, just as a photographer would do. Think like a photographer, place your lights accordingly, and your images will then have a more photorealistic and pleasing appearance.

[AdamT]

Or if all the light is coming from the windows, put omni or area lights in front of the windows.

But then, I think in most cases an omni in the center of the room won't look bad as long as it's very dim, i.e., only used to add a bit of ambience.

[LucentDreams]

coming from the illustrator point of view rather than the photographer point of view I say put lights where it makes the image look good andhelps to create modd or focus, I do agreer with MV on the whole put a light in the middle of the room. If I ever did that it would have to not cast shadows or specularity, be about 5% and be the dominant colour of the scene. But I doubt I would. keeping lightsources out of view is usually ideal IMO. but again its all opinionative and depends on what your going for. personally I would rather see someone doing achitectural renderings go more towards illustrative design rather than photorealistic, but I guess clients may want it to look as real as possible. I still prefer watercolour renderings over most 3D renderings. they make me say oooooh aahhhhhh a lot more than 3D rendering do.

[amapimaster]

Kaiskai - know what your saying there mate! Theres a guy where I work who can knock out a two or three colour marker render of an exhibition stand design in about an hour. His visuals are amazing - more about the feeling of a design instead of an accurate representation.

[MJV]

I was basing my comments on the fact that guy was looking for more realism. Think about this: How are going to make a realistic render by placing lights where they couldn't realistically be?

Originally posted by Kaiskai
coming from the illustrator point of view rather than the photographer point of view I say put lights where it makes the image look good andhelps to create modd or focus, I do agreer with MV on the whole put a light in the middle of the room. If I ever did that it would have to not cast shadows or specularity, be about 5% and be the dominant colour of the scene. But I doubt I would. keeping lightsources out of view is usually ideal IMO. but again its all opinionative and depends on what your going for. personally I would rather see someone doing achitectural renderings go more towards illustrative design rather than photorealistic, but I guess clients may want it to look as real as possible. I still prefer watercolour renderings over most 3D renderings. they make me say oooooh aahhhhhh a lot more than 3D rendering do.

[LucentDreams]

Originally posted by MJV
I was basing my comments on the fact that guy was looking for more realism. Think about this: How are going to make a realistic render by placing lights where they couldn't realistically be?

Do you always use 100% accuracy in radiosity??? do you always use caustics? Don't bother doing glass with out control ove rthe IOR either, lets be honest CG is not realistic, you should do what looks right not what should physically right, or else why use soft shadows or hard shadows, heck shadow maps at all are wrong, and then there is specularity, thats a total fake, and of course the blurred reflectinos is a fake. You see my point? Before we had radiosity n XL 7, to do a realistic scene rewuired lights all over the place, behind a bookshlef really subtle just to give the ilusion of the light creeping between the wall and the book shelf and such, now radiosity does that for us, but general lighting ADAM is sort of right that that a light in the middle could help, though you wouldn't want it creating anything that would ruin the believability like a shadow as a shadow from that direction is obviously wrong.

Look at spiderman, lighting in that film looked pretty good, they didn't even consider realism when they lit it though did they, n the interviews they had on cgchannel it was stated that they went for what looked right and not what is right ;)

[MJV]

Originally posted by Kaiskai
Do you always use 100% accuracy in radiosity??? do you always use caustics? Don't bother doing glass with out control ove rthe IOR either, lets be honest CG is not realistic, you should do what looks right not what should physically right, or else why use soft shadows or hard shadows, heck shadow maps at all are wrong, and then there is specularity, thats a total fake, and of course the blurred reflectinos is a fake. You see my point? Before we had radiosity n XL 7, to do a realistic scene rewuired lights all over the place, behind a bookshlef really subtle just to give the ilusion of the light creeping between the wall and the book shelf and such, now radiosity does that for us, but general lighting ADAM is sort of right that that a light in the middle could help, though you wouldn't want it creating anything that would ruin the believability like a shadow as a shadow from that direction is obviously wrong.

Look at spiderman, lighting in that film looked pretty good, they didn't even consider realism when they lit it though did they, n the interviews they had on cgchannel it was stated that they went for what looked right and not what is right ;)


Putting lights all over the place to fake radiosity is not wrong. You have to think of all those places where light is bouncing from as light sources, so you're doing the right thing when you place bounce lights there because light is supposed to be coming from there. You simulating a real phenomena. Specularity is a fake, but it's faking something real. Nothing wrong there. Soft and hard shadows are simulating real things. Again nothing wrong with that. I don't always use 100% accuracy in radiosity because it's just an estimate, a guess. It's up to the artist to determine if it under or over estimates what's needed. I don't think Maxon says anywhere that 100% mean 100% correct.

The goal is not to do what's rea. The goal is to do what looks real. Rooms aren't lit from magic lights in the middle of them, so it's quite impossible that adding such a light will look real. Such rigs are the hallmark of poor CG lighting.

As for Spider man, doing what looks right is exactly the right thing to do. A spot in the middle or a room doesn't doesn't look right, and that's why it's the wrong thing to do. But this brings us back into the realm of photography, doesn't it? As I said in my first post, there's nothing wrong with adding photo lights. You usually have to in order to get a pleasing balance, and architectural photography nearly always uses lights. You do it because it looks good, and directs the viewer's attention where you want it, and allows them to see what you want them to see. But you have to place them where they aren't seen by the camera, as I noted in my first post. I don't think Spiderman the movie had any magical middle room lights.

When you put a light where it can't possibly exist in 3D, your scene shows a pattern of illumination that tells the viewer where the light is coming from. If it's then coming from a source that should be within the viewers field of view, and yet it isn't, the eye will tell them that something is wrong even if they can't consciously articulate what it is. It won't look real, it won't right, and it's won't look good. ;-)

[MJV]

I will concede that a dim light in the middle of the room probably isn't going to do much harm. And I'm sure that if Hollywood did have magic invisible lights, they would use them. At least they don't require stands. :) I guess I was getting off on a theoretical bent there. ;)

[H. Ikeda]

Take it easy. So what is suggestion for the first question?
First of all, C4D's radiosity is not such kind of simulation but is simply one-way approximations (tracing of stochastic diffusion processes). You have to adjust the result, using strength and depth, so that the scene looks like realistic (whether realistic or not is up to us). The more depth is, the brighter the scene is. This means it has less consistency in its calculations. That is, only when you have a scene that looks realistic, it must be a good simulation for actual things in the scene. My suggestion is that you had better not use C4D's radiosity as lights, because it's not a consistent way of illuminating the scene. Just a small additional effect it should be.;)

[Cinema1954]

Sometimes a dim omni light (with no shadows) in the middle of the room is necessary to bring the shadow levels up to the point of visibility. The human eye is pretty good at seeing details in shadows; the rendering process isn't as good and sometimes needs a bit of help. I've worked in film and television lighting for over twenty years, and we often do the same thing by placing a soft light directly over the camera lens. The difference is that in photography we can't just turn the shadows off!

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