I've been looking at this weblink:
http://hdri.cgtechniques.com/~sibenik2/

the Sponza Atrium part of the website, which I'm sure most of you already know about. You can download the model in various 3d formats and then play around with various lighting settings.
I'm really interested to know whether any Carrara users have attempted to light the Sponza atrium scene, and hear from people who have used various techniques of lighting. Whether that be HDRI alone, and the careful placement of lights in the scene.
I've played around a little myself, but would be good to hear from some of our more experienced users here, as well as some of our less experienced users too.
If you have already rendered this scene in the past, I'd certainly like to see your images! (of course only if you're happy to post them as examples.)
I feel quite confident that Carrara is capable of rendering this scene just as good as those more expensive apps.

http://www.renderosity.com/viewed.ez?galleryid=557833&Start=1&Artist=goofball&ByArtist=Yes I did this scene in Carrara with only HDRI lighting. I think it competes with some of the other renders.

I see what you mean about competing with the other more expensive 'packages'. Did you use an HDRI image mainly made up of 'sky', or was it an image which contained other details in it?

Message edited on: 09/05/2004 17:10

Your image is great! Now you've got me hooked! Downloaded all the models and lets see how soon I can start cranking out some images! I'll let you now how it goes. :D

It was an HDRI map of a city, containing everything from the sky to the road. I cranked up the intensity I don't remember to what but it was high.

This looks cool. I am going to have to give this a go at some point.

FWTempsest, The darkness should go away if you select either Full Raytracing, uncheck interopolation or both. Mark

Mark... full raytracing is selected and interpolation is off...

Duh! I should completly read your first post before responding! Well that is exciting then. Increasing the photon count will probably help - but it may start driving the render time up longer than you'd like. However, there are two other things that I would try: 1) select the geometry in the vertex modeler (you'll need to convert it first) and crease the whole object to make sure Carrara understands that it's a completly flat surface, or 2) place a cube behind the far wall and allow it to intersect the wall slightly to prevent any "light creep" that may be occuring at the corner.

Speaking of which, what is the difference between "full raytracing" and not full raytracing?

Selecting Full Raytracing doesn't allow Carrara to "cheat" and save time while it's doing it's calculations. Using Full Raytracing forces Carrara to calculate the full path (4, 8 or whatever raytracing options you have set)of all rays instead of thinking, "these two light paths are similar so I'll only figure for one of them". Likewise, Interpolation for global illumination does something similar. Since doing the complete calculations for global illumination is very complex (takes time), interpolation accuracy simply tells Carrara how much "educated guessing" to do resutling in saved time. The default is 20% percent accuracy which is a bunch of guess work. That's why some renderings look so blocky - the guess was inaccurate. Eliminating or reducing the interpolation plus forcing Carrara to calculate all of the light rays gives a better result - but it will result in an increase in render time. Mark

Thanks, Mark, for the reply. I wish Eovia had included some comparative images on the Carrara CD to show how these options affect image quality and render time. Maybe if I'm feeling industrious one of these days I'll put something together for the Carrara community.

The render settings in Carrara are pretty ambiguous. But the manual does mention that rendering with "Improved Edges" checked will reduce the shadows in corners. I've never had to check that option to remove corner shadows (I call them ashes). I will post a render with the settings I'll be using. Right now I'm fixing the objects in the scene that have their texture brightness turned off. I imported the 3DS file after finding their OBJ file a nightmare to work on (it's all one piece).

I'm using the 3DS version too... I'm about to go to bed, but I'll check the Improved Edges and start this render again and sleep on it. Maybe that'll do the trick...

I rendered the atrium just now with 5000 photons (I think this is Carrara's default amount). I had ashes everywhere when using the Fast Quality Lighting setting. Using the director's camera, I noticed that the atrium model is pretty small. The diameter of the lens on my rendering camera is as wide as one of side hallways. I resized the atrium about 4-5 times larger and rendered again (with 5000 photons using Fast Quality Lighting). No ashes this time (or just very small ashes, smaller than a penny). Now I'm going to use 30000 photons to lighten up the darkened "cave" areas in the atrium (I probably only need 20000, though) and use Best Quality Lighting for my final render.

FWTempest, I'll be looking forward to seeing yours with textures. I assume textures will really bump up the render time. I havn't had much time,(unfortunately) but I will try and get my WIP version up real soon.

Message edited on: 09/07/2004 08:32

probably will bump up the render time a bit... especially with some 'bump' thrown in.... ;) This last one was about a 1 hour render @ 900 x 700... which I wasn't too displeased with, at all(of course, I'm used to using Bryce, also, which means waiting around all day for complex renders).

I think once you have textures turned on you can get away with much lower render setings because they mask the ashes quite will. I was wondering how to import the model without the need to crease all of the edges? Also how do you apply textures to this model in Carrara? It look like it will be an absolute nightmare.

That last atrium scene was very good. It's interesting to note how Carrara render times differ from Shade (Curious Labs) in regard to photon count. E.g. a Carrara render with 20,000 might take the same time as a Shade render with 1,500,000. I get the feeling that the two algorithms must define photons differently, and that Shade is undercalculating the effects as compared to Carrara.

I've been using: Ambient Lighting: 0% Sky Light: 570% Using a very light blue background (almost white). Indirect Lighting: 100% Photons: 20000 Best AA 1 pixel, 1 pixel Best Lighting 1 pixel Rendering with no textures, over 7 hours on my PIII-1000Mhz 512MB system. Came out looking perfect. Couldn't save it though (Unknown error occured). With textures & bump, over a day probably.

Shonner which file format are you trying to save in? I have some problems with .tif. If I want Alphas I use .psd. If you are doing a long render it also may be better to render to a file instead of saving after the render.

I've never had a problem rendering to TIFs on either platform. What problems are you having? And I agree about rendering to a file. If I have a large memory hog, like GI, then I render using the batch queue. Much safer, especially for animations, and more reliable for saving the file. If I'm just doing some tests, then I'm usually not interested in saving the image anyway. Just my 2 cents! :D

Shonner You need upgrate your system

Yes. I gave up on the Sponza model. Parts of the floor were missing in the render.

I think once you have textures turned on you can get away with much lower render setings because they mask the ashes quite will. I was wondering how to import the model without the need to crease all of the edges? Also how do you apply textures to this model in Carrara? It looks like it will be an absolute nightmare but you seem to have managed it well..

I used the .3ds version because of the smaller file size. There are already shading domains on the geomtery and the textures - if you download them from the Sponza site - simply go where they are supposed to. I don't know if the model has been opened without the textures, whether Carrara will "find" them, though. There was one bit of strangness for me. Some of the objects with the textures was pure black. I discovered that for some reason the intensity of the the maps was at zero instead of 100%. I just slide them to where they belonged and everything was fine.

Thanks for the info. I went with the obj file cause I thought that would be the best. I am not sure how far I will go with this though my puny Athlon 850 almost keels over when I crank up the render setting with this model! I need a new cpu baaaaaad.

Very nice indeed.

Thanks! :) Quite a fun challenge. Rendered with one spot light pointing into the Sponza top and and a light blue skylight if anyone wanted to know.

Looking good! The Dof is quite effective in adding depth to the scene.

Sweet. This is definatly a fun scene to learn and play with.