Let There Be Architectural Glass

Ernest Burden · September 22nd, 2004

I hope this model works, as I have put some time into it.

The idea is to test architectural glass materials in various rendering engines. I think a model with a glass ball or torus is not as telling as glass in an architectural setting. So I made a simple scene that has some areas for direct sun, indirect sun and basic interior lighting. The model has some stuff to reflect in windows, a glass table and some mirrors to get the most from any view.

Overall, its very basic, but should be a good platform for comparison.

The model is seperated into many layers and the layer color SHOULD be close, though a few colors seem to be shared between layers (which I tried to avoid).

The units are cm.

http://www.oreally.com/temp/glasstestDXF.zip

also see post #12 for .lp and .wrl versions

One other thing--the car is one of the free models from www.Lowpolygon3d.com with the texture removed, in the interest of disclosure. The rest I made.

Remember, materials by layer

Ernest Burden · September 22nd, 2004

The first try, in Lightscape (no post):

These took a few seconds to raytrace, less than an hour for full radiosity solution calc.

Ernest Burden · September 23rd, 2004

Well don't just all crowd in here at once!

As my stated goal is to develope better glass materials, I have been trying to render this scene in Cinema4D. I have started with the STRAT sky/GI-sky over the model, and STRATglass as the starting point, making a few mods.

So far, I have not gotten any decent results. The glass WAS performing well on the exterior, but once I got the interior light levels to where they needed to be, including the guessing of falloff amounts (Lightscape doesn't make you think about that, they just work) and the exterior views looked awful.

Also, the renderings are taking 1/2 hour or more from one sun and two interior omni lights. That is unworkable.

crazy homeless guy · September 23rd, 2004

i was hoping someone would chime in with a vray version. anyone...?? i could certainly use to learn how to do vray glass.

xgarcia · September 23rd, 2004

got this from this thread at the vray forums:

"Glass in my models allways has thickness since I use Vray. I take a thinckness of 10 or 15 mm. Sometimes more, depends on the complexity of the model (When there are a lot of glass planes I need to be able to find them, place and move then). IOR is mostly 1.4 unless I go for a 25mm or more thickness then IOR will go lower. When glass comes close to the camera and there is an environment to reflect, and I have the budget/ time, I do 25 mm with IOR of 1 and reflect on backside checked to simulate double glazing.
I have a basic black Vray material with glossy on 1 and reflection on 1 with a P/P falloff in the reflection slot. For the falloff, I allways change the line to a less steep one (so less maximum and more minimum). For the environment, it's more or less only the max environment slot that I use. But remember this is a montage. That means that I render the building with only a sky environment and a little bit of foreground as a tiff, and then mount it into the picture with the alpha map. Sometimes when a lot lot of environment buildings needs to be simulated, I render two versions. One with a sky environment and one with a remixed picture (with simulated junk buildings at the place of the building) and blend the two in PS.

Hope this answers your question.

Marc"

Hope that helps you Vray users. Thank Marc - he rocks.

Ernest Burden · September 23rd, 2004

Quote:

Originally Posted by xgarcia

"Glass in my models allways has thickness since I use Vray. I take a thinckness of 10 or 15 mm.....

Wow, that's a lot of words. In Lightscape you just select 'glass' and it look great. I am hoping that we can find where all those settings need to be to look like real glass, or better.

The glass in the supplied model does indeed have thickness and edges.

crazy homeless guy · September 23rd, 2004

Quote:

Originally Posted by Ernest Burden

Wow, that's a lot of words. In Lightscape you just select 'glass' and it look great. I am hoping that we can find where all those settings need to be to look like real glass, or better.

The glass in the supplied model does indeed have thickness and edges.

there is a setting in vray that allows you to make a plane of glass have a thickness, even though it is a single face. (at least i think)

Christopher Nichols · September 23rd, 2004

I will try a vray version maybe later tonight when I get home... What is the basic goal here? Make glass look more like glass? Or make glass react mroe like glass? Maybe both? The key is going to be in physics I think... a lot of research has been done of the centuries with optics. that Fresnel guy has a lot to do with it. Glass is the easiest one to unstandar Fresnel with... for that reason it will be the easiest to simulate... Lets see what we can do... For a good guide on this, I have found this site:

http://physics.nad.ru/Physics/English/rays_txt.htm

To be honest a still may be OK... but you are not really going to knwo if it "works" correctly unless you animate it...

wda · September 23rd, 2004

Quote:

Originally Posted by Ernest Burden

Wow, that's a lot of words. In Lightscape you just select 'glass' and it look great. I am hoping that we can find where all those settings need to be to look like real glass, or better.

The glass in the supplied model does indeed have thickness and edges.

Ernest,

Have you tried digging deeper into C4D materials and shaders, there are a couple fairly decent ones for glass-

Here is a tutorial that may help anyone using C4D to get a handle on glass
http://members.shaw.ca/jimht03/glass.html

Would you zip & post the Lightscape file, please. The C4D>dxf file into max has some monster flipped normal problems. Looks like about 1-2 hours to sort through all of it in MAX and clean up- it's really a polygon by polygon clean up.

Very Good Unchallenge Idea
WDA

Ernest Burden · September 23rd, 2004

Quote:

Originally Posted by Christopher Nichols

What is the basic goal here? Make glass look more like glass?
To be honest a still may be OK... but you are not really going to knwo if it "works" correctly unless you animate it...

I think 'looking good' is better than feeling good, as most of us produce images.

Animating would tell more, I agree. But do you find the images I did with Lightscape to be good, or even 'as good as you can ever expect'?

September 22nd, 2004	#1 (permalink)
Ernest Burden Veteran Member Join Date: Apr 2002 Location: Ossining, NY USA Posts: 4,999 Name: Ernest Burden III	Let There Be Architectural Glass I hope this model works, as I have put some time into it. The idea is to test architectural glass materials in various rendering engines. I think a model with a glass ball or torus is not as telling as glass in an architectural setting. So I made a simple scene that has some areas for direct sun, indirect sun and basic interior lighting. The model has some stuff to reflect in windows, a glass table and some mirrors to get the most from any view. Overall, its very basic, but should be a good platform for comparison. The model is seperated into many layers and the layer color SHOULD be close, though a few colors seem to be shared between layers (which I tried to avoid). The units are cm. http://www.oreally.com/temp/glasstestDXF.zip also see post #12 for .lp and .wrl versions One other thing--the car is one of the free models from www.Lowpolygon3d.com with the texture removed, in the interest of disclosure. The rest I made. Remember, materials by layer __________________ Ernest Burden III AcmeDigital architectural rendering Last edited by Ernest Burden; September 23rd, 2004 at 10:10 PM.

September 23rd, 2004	#3 (permalink)
Ernest Burden Veteran Member Join Date: Apr 2002 Location: Ossining, NY USA Posts: 4,999 Name: Ernest Burden III	Re: Let There Be Architectural Glass Well don't just all crowd in here at once! As my stated goal is to develope better glass materials, I have been trying to render this scene in Cinema4D. I have started with the STRAT sky/GI-sky over the model, and STRATglass as the starting point, making a few mods. So far, I have not gotten any decent results. The glass WAS performing well on the exterior, but once I got the interior light levels to where they needed to be, including the guessing of falloff amounts (Lightscape doesn't make you think about that, they just work) and the exterior views looked awful. Also, the renderings are taking 1/2 hour or more from one sun and two interior omni lights. That is unworkable. __________________ Ernest Burden III AcmeDigital architectural rendering

September 23rd, 2004	#4 (permalink)
crazy homeless guy Moderator Join Date: Nov 2002 Location: San Francisco Posts: 2,894 Name: travis schmiesing	Re: Let There Be Architectural Glass i was hoping someone would chime in with a vray version. anyone...?? i could certainly use to learn how to do vray glass. __________________ travis schmiesing

September 23rd, 2004	#5 (permalink)
xgarcia Senior Member Join Date: Jun 2002 Location: FL Age: 29 Posts: 471 Name: Xavier Garcia, Jr.	Re: Let There Be Architectural Glass got this from this thread at the vray forums: "Glass in my models allways has thickness since I use Vray. I take a thinckness of 10 or 15 mm. Sometimes more, depends on the complexity of the model (When there are a lot of glass planes I need to be able to find them, place and move then). IOR is mostly 1.4 unless I go for a 25mm or more thickness then IOR will go lower. When glass comes close to the camera and there is an environment to reflect, and I have the budget/ time, I do 25 mm with IOR of 1 and reflect on backside checked to simulate double glazing. I have a basic black Vray material with glossy on 1 and reflection on 1 with a P/P falloff in the reflection slot. For the falloff, I allways change the line to a less steep one (so less maximum and more minimum). For the environment, it's more or less only the max environment slot that I use. But remember this is a montage. That means that I render the building with only a sky environment and a little bit of foreground as a tiff, and then mount it into the picture with the alpha map. Sometimes when a lot lot of environment buildings needs to be simulated, I render two versions. One with a sky environment and one with a remixed picture (with simulated junk buildings at the place of the building) and blend the two in PS. Hope this answers your question. Marc" Hope that helps you Vray users. Thank Marc - he rocks.

September 23rd, 2004	#8 (permalink)
Christopher Nichols Moderator Join Date: Apr 2002 Location: Lalaland Posts: 1,166 Name: Christopher Nichols	Re: Let There Be Architectural Glass I will try a vray version maybe later tonight when I get home... What is the basic goal here? Make glass look more like glass? Or make glass react mroe like glass? Maybe both? The key is going to be in physics I think... a lot of research has been done of the centuries with optics. that Fresnel guy has a lot to do with it. Glass is the easiest one to unstandar Fresnel with... for that reason it will be the easiest to simulate... Lets see what we can do... For a good guide on this, I have found this site: http://physics.nad.ru/Physics/English/rays_txt.htm To be honest a still may be OK... but you are not really going to knwo if it "works" correctly unless you animate it... __________________ Christopher P Nichols

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