Hi All,

Just uploaded my latest tutorial to my site, about using Radiosity to make sunlighting work inside rooms with windows. This is a 2 part (at least) tutorial. Next time it'll be artificial room lighting.

Will try to have my 3D model room and the whole Vue scene (if you have a high speed connection and plenty of patience) ready for download tomorrow, in case you want to play with the original.

Pix:

Enjoy!

_jc...'Art Head Start' e-book
.......Art Head Start.com site
Art knowledge and skills for digital artists. Free chapter on lighting, Vue tutorials and models.

Looks like a very intetesting tutorial,but i bet the render times are a killer:D Thanks for sharing your knowledge(;

With "User" render settings, the render times can be surprisingly low - but you might want to boost the numbers somewhat over what i show, to get better quality. I went for shorter render times.

But you're right, Radiosity has its price, since it has to evaluate the brightness relationship of every pixel to every other pixel. Pretty amazing to me that a personal computer can even be coaxed into doing that.

I agree that it's not wise to use Radiosity where you don't really need it.

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

Message edited on: 01/23/2006 11:32

Jim, Thanks for sharing this! Definitely helps a newbee like myself to learn Vue. Can't wait to check out the Vue scene that goes along with it...MG

@jc But honestly,where would one NEED radiosity? Where does GR exist in nature? May sound dumb,but honestly i dont know even.Is natural light GR? is it office lighting? I understand what GR is,but i havent seen it to my knowledge,not the way Eon explains it anyway.

Seems to me whether one needs the Radiosity lighting solution is a personal choice, like all the other choices that go into an image.

It is the most realistic lighting method in Vue. If there is a place where you really should use Radiosity, i'd say indirect interior lighting (e.g. sun through window, no simulated light fixtures) is it.

Try lighting a room interior where sun through a window (no electric lighting) is simulated - with and without Radiosity and i think you'll agree. And there have been several posts here showing poor results without radiosity in the past.

In general, it will only apply where there are reflective surfaces (not dark surfaces) near each other, or where you want very realistic skylight and shadows.

"Where does GR exist in nature?" Everywhere. In the real world, most surfaces both absorb and reflect light. That reflected light can illuminate nearby surfaces and they, in turn, can light other nearby surfaces. Look around you and you'll see this hapenning nearly everywhere.

So far, only Radiosity can simulate this realistically in Vue. Global Ambience fakes it. Global Illumination fakes it better. Global Radiosity actually calculates and simulates it.

But not every scene is going to look better with Radiosity, especially if you don't sufficiently boost the ambient light in your scene.

Test it for yourself and decide if it's worth the extra render time.

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

BTW, here is my test scene with and without the Radiosity turned on, no other changes (as i show in the tutorial):

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

my bad english can't help me to explain well my opinion... but i will try however... 1 - i agree with JC, Radiosity is everywhere, imagine a white room with red carpet, and the light of sun come from a window and hit the carpet... what do you think that can happen in the white room ? some red and "pink" artfact go around the room ? well this is one of the effect of GR... 2 - about your image JC... i'm not sure about the realism of your work (don't be offended ! you are doing and incredible work and a very professional tutorial...) but, imho, in the specific image of this post the result is not so good... in real world, is very hard to see the green color of leaves "reflected" as your image, and in general the light is too Strong and cold... by the way, i think the rendering engine of GR in vue will be improved in next release, i prefer use only the GI, not so satisfied both of performance (to slow) and result (to "unreal" in many cases)... Bye Luca.

Attached Link: http://http://www.renderosity.com/viewed.ez?galleryid=1135977&Start=1&Artist=Samhain74&ByArtist=Yes

Thanks for your comments rodluc2001.

I agree that i went somewhat too far and applied too much GR to the scene. I will do another render. For example, the shelves in the backroom look like they have a light source sitting on top, because too much light is being reflected from them onto the back wall. I also applied too much cyan to the point source, as the ceiling was going magenta. It could certainly look warmer.

Will have to find time to do make those changes though. In the meantime, i hope my tutorial will still be useful. Just don't overdo the Radiosity folks.

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

Message edited on: 01/23/2006 16:20

your tutorial is great, and very, very professional !!

Hey thanks Rodluc - much appreciated!

Well, here is a new radiosity render of the test room. Reduced the Radiosity gain and especially the Ambient Vs Sunlight and Sky Dome. Added an orange bias to the Radiosity (maybe a bit too much?):

Above is the last one again. Notice how the corners and edges are much better defined and there is less indirect reflection? Oh, and i had to change to a VUE 5i default tree for the upcoming tutorial model download, since the nice "Incredibly Lush" one (from C3D) is not a freebie.

Comments welcome :o)

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

Message edited on: 01/24/2006 13:12

very improved ! if you want you can send me the zip of the scene... will be nice try some experiment on this room ! my mail is rodluc@virgilio.it !

let me know ! remember to incorporate maps when you save the scene ! :)

Message edited on: 01/24/2006 13:12

Yes, nothing like an hour of serious tweaking to make those subtle improvements, lol.

Sure Rodluc, but instead, i'll be making it available to everyone as a download in the next day or two (as part of the tutorial). Will post here when it's ready for download.

Trying to make my tutorials more useful by providing all models in future. Even bought Camtasia Studio and a new sound card, so i can record video tutes, plus SWF files to work inside Vue help system and such. This will slow tutorial production, so i'll keep putting plain tutorials on my site at the same time.

Cheers! _ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

excellent JC !! i'm really interested ! and i want understand if the GR engine is good enough... and if my nad results are simply 'coz ' don't use it very well...

Sorry to disagree folks, but the only render that looks realistic to me is the one with the Radiosity turned off!! The rest of them are far too bright inside the room. The contrast between the inside surfaces and the outdoor view should be very high.

Personally, I dont think Vue is up to snuff for interiors.

@dadt : if you read the all the post you can see that also i'm not satisfied from the GR vue engine... but i think that vue GR can be used better... @RyanSpaulding : i disagree..i'm not a master of vue, but take a look in the interiors scene : http://www.renderosity.com/viewed.ez?galleryid=1100461&Start=1&Artist=rodluc2001&ByArtist=Yes http://www.renderosity.com/viewed.ez?galleryid=823482&Start=19&Artist=rodluc2001&ByArtist=Yes and http://www.renderosity.com/viewed.ez?galleryid=759153&Start=19&Artist=rodluc2001&ByArtist=Yes not so bad as interior scene...

I did not meanto say that the GR is no good, just that it needs to be used carefully. In a real room lit by a window there are very high contrast levels between different areas, and the window, which is the light source, is much brighter than anything else.

oh, i completly agree with you... but you must use carefully the Radiosity of vue engine ! :) (imho) coz in other radiosity-enabled render engine, this don't happen (try with cinema 4d or 3d studio max, GR setup is most realistic without to much careful...) i hope the next version of vue compatible with mental-ray or v-ray, or something like that... but maybe only a dream...

I don't think it would be hard at all to make the room darker - i was trying for a very light, bright, open look (which seems to be what people have trouble with in Vue interiors). That is, realistic while not physically accurate.

In general, i'm interested in simulating reality as an art form, not recreating accurate physical reality in 2D - i usually use a digital camera for that.

Maybe i'll try a more physically exact render though - just to see how it looks. Hard to do with the limited dynamic range of a monitor (maybe 100:1) Vs human vision (about 30,000:1 in a single environment). My bright scene doesn't need such a high dynamic range.

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

Jim, can't find a link to your site, only to your book!

Sorry for any confusion. The bottom link in the post above yours goes to my e-book site (same as the link at the end of this post).

Tutorials are on the same web site as my e-book.

Look down the home page (big masthead pix of earth on home page) on the left for the navigation system. It shows the tutorial pages.

Here it is again: Art Head Start.com site

This one goes to tutorial summary page: Free Stuff

Thanks Jim, I hadn't noticed the menu on the left.

Right - i did a usability "no-no" by having that big masthead image and letting the navigation slip so far down the page. Glad you got there all right. :o)

This looks useful. Thanks!

Attached Link: http://www.renderosity.com/viewed.ez?galleryid=1140867&Start=1&Artist=chippwalters&ByArtist=Yes

I found an existing picture to work from which helps a lot.

JC, did you check 'Indirect skylighting' for radiosity? If you do, it takes more time and is a bit more textured, but I think it will generate a better finished image. I notice light areas above your shelves which IMO wouldn't be there. Indirect lighting will fix this. Just a suggestion.

-Chipp

Hi Chipp! Thanks for the suggestion - and the great example. Lot of value on your site! (Google his cool 'AltTerrain Builder' folks).

No i didn't use it, the help indicated that 'Indirect skylighting' was very compute intensive and not usually much better. But i'll give it a try now.

Some amount of light reflected off the shelves (depending on their material settings) is realistic, IMO - but i certainly had way too much in my first posted image.

I would warn against the other checkbox, 'Indirect reflections', if you have any reflecting surfaces, like my glass tabletop. I got severe "speckled" artifacts from that - reflection of sun outside, i think.

Help sez: "This results in typical caustic patterns around reflective objects at the cost of a lot of additional processing. It is usually recommended that you disable this option, as the results it produces are useful only under very special circumstances."

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

.

My Vue 5i room lighting .VOB test model object (including all the props) is now Zipped up and ready for download. Went from 20MB .VOB to 7MB .ZIP!

Had no idea .VOB files would compress so much!

Notes: I had to list all the lights in a separate layer before Vue would let me group all the room elements. You might want to ungroup the model and move the lights back into their respective models in the object lists. The light sources are still in their correct physical locations in the actual model though - only the object list was changed.

Room Lighting Test Model.

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

Message edited on: 01/26/2006 12:25

Took Chipp's advice and tried a Radiosity render with that "Indirect skylighting" checkbox on (in Atmosphere Editor's Lighting setup for Global Radiosity). 6Hr 17Min render.

I also combined slices from each of my Radiosity render examples for easier comparison.

My choice would be about 1/2 way between the top 2. That is, like the top one, but with more Radiosity gain.

My tutorial is updated for this new stuff.

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

The lighting on the tree on top1 looks very nice, with shadows and translucent effect on leaves, but the surrounding walls are a bit too dark. On top2, the walls are more correctly lit, imho, but no nice lighting effect on the plant. Hard choice. Maybe the increase of render time for indirect skylighting will make the choice for us.

Thanks for the inspection, bruno021.

I agree that the top one is too dark. For me, the top (latest) test works best, but just needs more Radiosity gain after turning on the "Indirect skylighting".

It's the old story - "final renders" are never final, but can almost always be improved. Too bad it takes overnight to find out and try again.

I'm moving on to other tutorials now :o)

_ jc...'Art Head Start' e-book
.......Art Head Start.com site Art skills for digital artists. Free lighting chapter, tutorials.

Thanks for the hard work you're doing for us Vue'ers. Like iloco would say, not much free stuff around these days.

Jim,

I tried a few times unsuccessfully to render your scene, but it kept hanging on the anti-alias pass. In any case, if I get it rendered I'll post it.

In the meantime, I did some judicious cropping and a simple level adjustment to one of your above images, and I think it works pretty well.

IMO, the woman standing should probably go, as she competes with the tree as the center of interest by looking out the window, and is a dead giveaway this is a computer rendering. Perhaps having her facing the tree with her back to the camera would be more appropriate. Also, an alpha plane with an outdoor scene would help outside the window as another photorealistic cue. Just my 2 cents.

Chipp

Well, thanks Chipp. But this was never intended as a gallery entry, fine art piece, etc. It's strictly utilitarian, for lighting tests and tutorials. The figure is for scale and to show lighting on an organic shape and you cropped out the ceiling light fixture i'll be using in future artificial light room renderings, lol. Wonder why it wouldn't render. Maybe WinZIP damaged it? _jc

Hi Jim, I know it wasn't intended as a gallery entry, but when trying to simulate reality, every little bit helps:-). I think it's often difficult to separate content from composition, as both are quite intertwined. A professional illustrator friend of mine pointed that out to me on occasion. I think I'm getting it this time but I'm using a much lower AA setting which reduces the quality of the image. Hopefully it'll finish. best, Chipp

Good point, Chipp. I guess even a tutorial image is a better instructional tool if it supports the best practices of visual communication.

Cheers!
_jc

Hey Jim, here's a very small image of what I was working on. It uses a spotlight outside the building with volumetric effects for the 'sun' and another above the tree as well. You can see the AA isn't very good.

Then there's a single point light in the middle of the room just above where the light hits the ground and it's shadows are set to very soft (not ray-traced). The whole thing is done with radiosity, but no indirect skylight, so it renders faster (?)!

I've been doing some test using indoor global illumination. I'll try and post a tutorial when I'm done. Message edited on: 01/30/2006 19:51

Hey great Chipp! I've been wanting to try volumetric lighting in the room model as well. And i see you've added a backdrop out the window. Nice! _jc

Jim,

Remember, you don't have to set the sky setting to volumetric, you only need to use volumetric settings for your spotlights. That's why I changed the directional light to a spotlight.

During daytime, I don't think interior lights have much affect on the scene, that's why I try and keep the number of lights to a minimum. It would be interesting to do a dusk or sunrise scene like the PHOTOGRAPH above.

The friend I mentioned to you, his name is Syd Mead and he's quite an accomplished illustrator. His photo reference library is amazing. He keeps every picture he's ever ripped out of a magazine and files it away, and ends up using them for composition studies, lighting models and color schemes. (Google Syd Mead).

It's probably one of the best ways to learn. Find a picture and try and duplicate it.

-C