Glass Help

Hey all, So I’m using Blender 2.74 and have been learning for the better part of a month now and am having a blast. So I’m learning thru the use of the many tutorials and sites like this one and I am running into the issue of to many out dated tuts. I’ve learned to steer clear of the really old ones but even 2.7 seems to have differences at least in the result I’m seeing on my screen. Sorry kinda ranted there, now back to my question. I was inspired to use the start cube as a glass holding an object inside by this render I saw on r/Blender

There was a healthy back and forth about the validity of the claim that this was a first render by someone who had only been using Blender for a short time… I digress…so here is my image

and a screen shot of the setup

I’m looking to cut down on the graininess overall as my main goal. I’m at 200 samples, clamp direct is 7 and indirect is 3. The light is from a plane directly above, color white, strength of 7.
The head in the center was very quickly done and is just a representation of an idea.
Help refining the image would be greatly appreciated. I look forward to any an all comments!


I’m not exactly sure I understand your node setup…

Why mix two glass shaders with a constant mixing factor? That’s essentially like using one glass shader with an arithmetic mean for the roughness setting.

You’re mixing your combined glass shaders with a diffuse shader based on Fresnel - but with the diffuse as the bottom input. As a result the material will get more diffuse and less “glassy” at glancing angles - but why? This is exactly what causes your cube to have a kind of solid “frame” around the bottom, top and sides.

BTW, 200 samples is really not that much. Do 2000 samples and then we talk again…:wink:

The node setup is based off a glass node setup I found on a youtube tutorial that had a good result, but i guess not for my application. I’ll adjust and up the samples…stay tuned and thanks.

It is? I get two layered roughness effects for this, and obviously one if I only take the middle value (or do I misunderstand "mean average maytbe?). Just like we sometimes do for layered gloss (slightly rough plastic with a smooth top coat i.e.). Not sure if it is a “valid” glass to do something like this, but still… :slight_smile:

I stand corrected then - not going to argue about this…:smiley:

It’s looking better in the viewer…the computer i’m on now will take hours to render at 2000 samples so ill render tonight and post.
thanks again! Oh and as a complete novice your short back and forth is like a different language :slight_smile:

Managed to render a 1000 sample image with new settings…much better! still want the head to be brighter…ill work on it.
Thanks IkariShinji!

A few things that might help.
Make sure that the glass shader is set to a pure white color:

Even the slightest “non-white color” will make the glass look greyish (as we possibly see in your render).
Left: Pure white glass / Right: Slightly off-white glass

Try if enabling “Multiple Importance Sampling” in your light sources helps speeding up the render.
Are you on a very old computer? Still a bit puzzled by your excessive render times. Just to be sure: You don’t have “Square Samples” checked, do you? 2000 samples + “Square Samples” = 2000 x 2000 samples = 4000000 samples…

On my way home to my (much more powerful) computer. I’ll check these settings and give it another render a 2000.

Ok render time is down to 30 min…so thats better. Like the way this is looking! I know I saw somewhere how to get rid of the reflection of the head on the sides of the glass but I can’t find it. Any ideas, I’ sure it something simple…
Thanks again IkariShinji for all your help.

Best one! but I dont like the right side reflection.