Lighting Challenge #4: Bottle Collection

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  05 May 2006
Brians scene

Quote: Alright, so I lied...I pulled myself back to the computer for a few more hours and made a few changes...I'm out of town tomorrow though and then it is back to work on monday, so I am not quite sure when I am going to get some more time to work on it, but I would love some feedback/suggestions for when I do some get more time, if people are willing...

Looking forward to seeing other entries in the next few days!

Thanks again.

-Brian


Brian, I like the colored glass you have set up. What renderer are you using?

I played around with the ray recursion limit and it seems if I drop it down to 6-8 the glass gets very dark. The last post it was set at 16 and my computer was crying on that render.

What limit or value do you use?

Thanks,
Slatr

Last edited by slatr : 05 May 2006 at 05:21 AM.
 
  05 May 2006
Originally Posted by slatr: Brian, I like the colored glass you have set up. What renderer are you using?

I played around with the ray recursion limit and it seems if I drop it down to 6-8 the glass gets very dark. The last post it was set at 16 and my computer was crying on that render.

What limit or value do you use?

Thanks,
Slatr


I am using xsi with mental ray as the renderer...I am not looking at my scene right now, but I believe that I have the ray depth set at 12....I don't believe that it is getting through quite all of the glass, but it is pretty close. I think that to be able to get through all of the glass you are going to need a higher setting than 6 or 8, but maybe not quite as high as 16....The render times actually aren't really all that bad right now (I think it took about 5 min to render my image...) , but my lighting set up is pretty simple still...just a few detail shadowmapped spotlights and a point light without shadows, no GI or caustics.

Anyways, good luck with your scene, looking forward to seeing your progress.

Thanks for the comments as well.

-Brian
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-Brian
 
  05 May 2006
That looks like a good start. I like how you have some etching on one of the bottles.

I don't know if the background is too saturated; maybe the background's fine and the lights motivated by it just need to be more blue. Maybe the lights coming through the window could be a focused moonlight that casts relatively crisp shadows, plus a blue sky fill that's much softer. Then you'd just need some fill/bounce from the inside and some reflections of the room onto the bottles. The window trim looks like it's getting a flat ambient light or constant shader of some kind, some shading there would help.

It helps to keep the same shader on all the bottles until you are happy with it, before you clone it around and add variety. That way you can work on issues like making the bottles cast shadows, etc. all at once, and only adjust separated shaders for fine-tuning.

-jeremy

Originally Posted by slatr:

More experimentation. I have isolated the bottles as a group. I am trying to decide what I want to do with them.

My lighting has a blue cast to it, but I believe my background image is too saturated.

I need to try some colored glass on some of the bottles and deal with the background image.

Please comment or critique, I am learning.

Thanks,

Slatr
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  05 May 2006
Originally Posted by meanlebh: Alright, so I lied...I pulled myself back to the computer for a few more hours and made a few changes...I'm out of town tomorrow though and then it is back to work on monday, so I am not quite sure when I am going to get some more time to work on it, but I would love some feedback/suggestions for when I do some get more time, if people are willing...

Looking forward to seeing other entries in the next few days!

Thanks again.

-Brian


Those bottles are looking good!

There's a need for some sky/fill light coming through that window. It looks now almost as if all the light is coming through the window from the same angle, when really it looks bright outside and you'd expect soft illumination spilling in from the whole rest of the sky, not just the sun.

I think some of the raytraced shadows need a greater ray depth. RIght now the trim along the lower base of the window is brighter in a few areas where you see it thorugh the bottles than where you see between or around them, making me think there's a shadowing bounce light that needs its shadows to be visible through more layers of refraction.

Looking forwards to more!

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  05 May 2006
Microphone check one,...

Hey guys heres my first test. Im sure all of you with the mental rays and vrays and brasils are going to kick my glasses ass but here goes Maya Software. Im planning to test this with Renderman for Maya too. What a tedious assignment though : )

link to 2k render

http://dirtylenses.com/Images/Bottles1.jpg

cheers
Attached Images
File Type: jpg Bottles1Small.jpg (86.9 KB, 2235 views)
 
  05 May 2006
Originally Posted by Ergi: Microphone check one,...

Hey guys heres my first test. Im sure all of you with the mental rays and vrays and brasils are going to kick my glasses ass but here goes Maya Software. Im planning to test this with Renderman for Maya too. What a tedious assignment though : )

link to 2k render

http://dirtylenses.com/Images/Bottles1.jpg

cheers


The glass (of the glass bottles) is looking good! The window glass needs work, that "crackle" texture isn't very convincing, it's very regular, and then it melds with the twigs of the tree you see through it and looks confusingly like a reflection of the tree outside in places. Speaking of "outside" the tree seems to come through the window a bit on the left. Then the metal parts of the window, that should be opaque, have a blurred shadow of the tree on them. It looks like maybe that was a compositing error, maybe putting a glow around the sky that bled over onto the metal, but still it looks strange.

Apart from the strangenesses of your test, it is looking good. Maybe some of the glass bottles could be going too dark, for bottles sitting right by a window like that, but the bump mapping is working on them. Why do you think the reflection of the 3rd from right bottle looks so bright and clear in the bottle behind it, when the bottle itself is so dark? Is it a shadow with too low a ray depth limit maybe? Or the shader needs more light absorbance?

(I've just been playing with some of those Maya raytracing parameters for glass. Funky stuff! Like the way any non-zero "surface thickness" cancels out the "light absorbance," but light absorbance is mostly only seen in reflections and refractions of the bottles, not the bottles themselves...)

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  05 May 2006
refraction

I am not certain my refraction is working.

The tutorial I read said (in lightwave) to copy and paste the geometry, flip it, and then assign the flip the air refractin value. The first set of geometry would have the 1.52 value.

I will go back tonight and try to isolate this before I work on the items Jeremy said to look at.
 
  05 May 2006
Originally Posted by slatr: I am not certain my refraction is working.

The tutorial I read said (in lightwave) to copy and paste the geometry, flip it, and then assign the flip the air refractin value. The first set of geometry would have the 1.52 value.

I will go back tonight and try to isolate this before I work on the items Jeremy said to look at.

The bottles are already fully modeled in terms of having an inside and an outside, so no additional copies should be necessary. Just render them with some subdivision or polygon smoothing, as double-sided surfaces (if there's a choice to turn off back-face culling and render front and back, although that might happen automatically for transparent objects.) 1.52 is a little high for glass, I see some refraction but not that much in your render, maybe because you did something else to counter-act it. You don't need to worry about doing anything for the refraction level of air. A single IOR value should be used on the surface, and the entrance and exit refraction angles should will be computed by the raytracer as long as the bottles are rendered as double-sided surfaces. (Yes, even the Klein Bottle. )

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  05 May 2006
Thanks!

Thanks Jeremy, I will go back to the original file, isolate the bottles, and make them double sided.

As far as the etching, I appreciate the comments. However, that was an accident if it wasn't in the original geometry.


EDIT: Here is that site I was checking out http://www.robinwood.com/Catalog/Te.../LWGlass-1.html

Last edited by slatr : 05 May 2006 at 03:56 PM.
 
  05 May 2006
Thanks for the comments and suggestions Jeremy. I definitely agree with your comments and will be hopefully getting a chance to work on it a little bit more this coming weekend or maybe in my evenings at work....Thanks again!

-Brian
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-Brian
 
  05 May 2006
I rather have a bottle in front of me than a frontal lobotomy....

Some simple test....


/Z
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  05 May 2006
Originally Posted by jeremybirn: The glass (of the glass bottles) is looking good! The window glass needs work, that "crackle" texture isn't very convincing, it's very regular, and then it melds with the twigs of the tree you see through it and looks confusingly like a reflection of the tree outside in places. Speaking of "outside" the tree seems to come through the window a bit on the left. Then the metal parts of the window, that should be opaque, have a blurred shadow of the tree on them. It looks like maybe that was a compositing error, maybe putting a glow around the sky that bled over onto the metal, but still it looks strange.

Apart from the strangenesses of your test, it is looking good. Maybe some of the glass bottles could be going too dark, for bottles sitting right by a window like that, but the bump mapping is working on them. Why do you think the reflection of the 3rd from right bottle looks so bright and clear in the bottle behind it, when the bottle itself is so dark? Is it a shadow with too low a ray depth limit maybe? Or the shader needs more light absorbance?

(I've just been playing with some of those Maya raytracing parameters for glass. Funky stuff! Like the way any non-zero "surface thickness" cancels out the "light absorbance," but light absorbance is mostly only seen in reflections and refractions of the bottles, not the bottles themselves...)

-jeremy



Jeremy,..at the moment all my shadows are simple 512x512 dmap shads. That accounts for a lot : ) Also the reflection coming from inside the room is a plane that leaves black space on the sides to be reflected.

I initially wanted to use rman for Maya and deep shadows to test the eval version, but the watermark was a bit of a pain. So i thought i might "fake" the whole thing. Like project fake caustics from a top light and so on.
A few of my lights also have gobos on them so thats what creates the light variation on the window ledge and the shadowing on the window frame (which right now is only a default blinn).
As far as the Maya raytracing parameters,.. theres indeed funky stuff going on. A slight difference in shape from bottle to bottle produces totally different results. I have yet to play with light absorbance.

I will post some screenshots. Even with dmap shads there is at least one bottle that sort of works already : the first one on the left and right. I am still getting dark edges on it, but i kinda like where its going.

Some screenshots

and links to full res

http://dirtylenses.com/Images/Screegrab1.jpg
http://dirtylenses.com/Images/Screegrab2.jpg
http://dirtylenses.com/Images/Screegrab3.jpg
Attached Images
File Type: jpg Screegrab1Small.jpg (38.8 KB, 572 views)
File Type: jpg Screegrab2Small.jpg (57.1 KB, 362 views)
File Type: jpg Screegrab3Small.jpg (58.9 KB, 296 views)
 
  05 May 2006
Okay here's my first attempt at this one. I just grouped the bottles together and threw a glass material on them to test the light setup. I'll definitley put some more work into this.

 
  05 May 2006
sjmcc -

Thanks for inviting other people from the C4D Cafe. Your image looks a little too early to say much, just because I can't tell if it'll be indoor or outdoor lighting or what kind of setting you're going for, and it doesn't have much in the way of backgrounds or reflections yet. If the bottles are going to stay that green, then the shadows where light has filtered through them should be going green as well.

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  05 May 2006
whoaw..master zap..very nice image you got there.

okay, heres my first take on the challenge. so far the shader works on some of the bottles. i only used one shader for all of them. when i come back tomorrow,hopefully i could texture each one of them right.
the lighting i think needs more tweaking. i used maya software render for this image. its a club scene.

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Last edited by herbertagudera : 05 May 2006 at 02:14 AM.
 
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