# Accurate liquid in glass rendering **URL:** \ **Category:** Blender and CG Discussions\ **Tags:** rendering, materials\ **Created:** [June 16, 2022, 8:24am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201 "2022-06-16T08:24:16Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 8:24am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/1 "2022-06-16T08:24:16Z")
When you use thin glass, you can not notice problem. But use thick glass, you can easiliy notice problem if you intersect your surfaces. Example real life thick glass: ![](https://blenderartists.org/uploads/default/original/4X/6/b/c/6bc6094fecf2ec2c747dffc99daa879dddf74092.jpeg) You can easily see thick glass part. But, if you intersect surfaces, then this glass not show, and result will be wrong. ---
**Author:** ![Calandro](https://blenderartists.org/user_avatar/blenderartists.org/calandro/32/976477_2.png) [@Calandro](https://blenderartists.org/u/Calandro)\ **Post date:** [June 16, 2022, 8:42am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/2 "2022-06-16T08:42:06Z")
Are you sure about that? I made a test here and it looks ok to me. ![image](https://blenderartists.org/uploads/default/original/4X/c/5/b/c5b067a0f9f3fabd7f9ec828c6157933b109c9e1.jpeg) Well, maybe it’s not the best example, but I didn’t make it look beautiful, anyway. ---
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 8:59am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/3 "2022-06-16T08:59:48Z")
I am sure. You did not intersect. ---
**Author:** ![Calandro](https://blenderartists.org/user_avatar/blenderartists.org/calandro/32/976477_2.png) [@Calandro](https://blenderartists.org/u/Calandro)\ **Post date:** [June 16, 2022, 9:07am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/4 "2022-06-16T09:07:04Z")
Yes, I did intersect. Why would I say that if I didn’t have? ![image](https://blenderartists.org/uploads/default/original/4X/2/0/1/2015eeab061dea9ac00cdf0ac9527af78dcbc2b1.png) Actually, what I forgot in that other image was to invert the normals of the liquid as they were pointing inside instead of outside. This is the correct image: ![glass](https://blenderartists.org/uploads/default/original/4X/d/4/1/d4125aab2419566e48a329d3ea7f72e35c737163.jpeg) ---
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 9:08am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/5 "2022-06-16T09:08:54Z")
I don’t see well. You can send blend file. ---
**Author:** ![Calandro](https://blenderartists.org/user_avatar/blenderartists.org/calandro/32/976477_2.png) [@Calandro](https://blenderartists.org/u/Calandro)\ **Post date:** [June 16, 2022, 9:10am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/7 "2022-06-16T09:10:17Z")
Let me just remove the HDRI. ---
**Author:** ![Calandro](https://blenderartists.org/user_avatar/blenderartists.org/calandro/32/976477_2.png) [@Calandro](https://blenderartists.org/u/Calandro)\ **Post date:** [June 16, 2022, 9:17am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/8 "2022-06-16T09:17:19Z")
[glass.blend](https://blenderartists.org/uploads/short-url/6Mu6b48hxu7XEOk4H2pnuyGCJIY.blend) (2.6 MB) Sorry, I applied the subdivision and the file became bigger than it was supposed. ---
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 9:24am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/9 "2022-06-16T09:24:40Z")
Which Blender version you use? Blender crashed when I open this file. ---
**Author:** ![Calandro](https://blenderartists.org/user_avatar/blenderartists.org/calandro/32/976477_2.png) [@Calandro](https://blenderartists.org/u/Calandro)\ **Post date:** [June 16, 2022, 9:35am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/10 "2022-06-16T09:35:34Z")
Blender 3.2 I can save it in another version. Which one do you need? ---
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 9:41am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/11 "2022-06-16T09:41:24Z")
It doesn’t matter. Maybe you saved when in the Edit Mode. When do this, Blender may crash when open this file. ---
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 10:27am UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/12 "2022-06-16T10:27:56Z")
You intersected a little bit and problems begin. If I increase intersection amount, then this artifacts will cover all of the glass. ![Intersected](https://blenderartists.org/uploads/default/original/4X/f/f/3/ff3d3bcd8425ca8f771be7a07d8d1fcb318875c4.jpeg) This is non-intersected result: ![Non-Intersected](https://blenderartists.org/uploads/default/original/4X/c/f/9/cf9de6a73b7c10238f4b6553a5fcbe629bc54bfc.jpeg) You can see, wrong reflection and refraction gone. ---
**Author:** ![SterlingRoth](https://blenderartists.org/user_avatar/blenderartists.org/sterlingroth/32/3107_2.png) [@SterlingRoth](https://blenderartists.org/u/SterlingRoth)\ **Post date:** [June 16, 2022, 3:49pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/13 "2022-06-16T15:49:18Z")
Not if you are compositing the background in. you’ll get some of the reflections, and some of the refractions, but it will just turn the transmission into straight alpha. anything you composite in will not be refracted, which will really flatten the effect. ---
**Author:** ![SterlingRoth](https://blenderartists.org/user_avatar/blenderartists.org/sterlingroth/32/3107_2.png) [@SterlingRoth](https://blenderartists.org/u/SterlingRoth)\ **Post date:** [June 16, 2022, 3:52pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/14 "2022-06-16T15:52:48Z")
@Calandro & @Hikmet Read this article: > **[Fluid in a Glass - Adaptive Samples](http://blog.gregzaal.com/2013/10/19/fluid-in-a-glass/)** > > (and why you’ve been doing it wrong your whole life) It’s hard to imagine a world without wine-glass tutorials, there are hundreds of them! Heck, I made two myself a few years ago. But there’s a problem! We’ve been teaching (and learning) the wrong... @usernew already posted it, but it looks like you both ignored it. This is the correct way to render fluid in a glass with proper IOR on each interface. ---
**Author:** ![Hadriscus](https://blenderartists.org/user_avatar/blenderartists.org/hadriscus/32/978263_2.png) [@Hadriscus](https://blenderartists.org/u/Hadriscus)\ **Post date:** [June 16, 2022, 3:55pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/15 "2022-06-16T15:55:13Z")
Ah, that’s the one. Couldn’t find it. It’s going right in favourites, thanks. ---
**Author:** ![Calandro](https://blenderartists.org/user_avatar/blenderartists.org/calandro/32/976477_2.png) [@Calandro](https://blenderartists.org/u/Calandro)\ **Post date:** [June 16, 2022, 4:38pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/16 "2022-06-16T16:38:13Z")
But who said the interception should be big? Actually, the interception is supposed to be minimal. Just enough to make the liquid intercept with the glass, If it can be imperceptible, the better. ---
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 4:49pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/17 "2022-06-16T16:49:26Z")
My friend, this article is not an academic article, right? ---
**Author:** ![SterlingRoth](https://blenderartists.org/user_avatar/blenderartists.org/sterlingroth/32/3107_2.png) [@SterlingRoth](https://blenderartists.org/u/SterlingRoth)\ **Post date:** [June 16, 2022, 4:52pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/18 "2022-06-16T16:52:55Z")
It is not, but it is an accurate assessment of rendering liquid in a glass for CG artists. It is based on accurate physics. You need to model the water/glass interface as a single surface with the normals correctly setup. Liquid inside the glass is wrong, liquid intersecting the glass is wrong. It needs its own interface surface. ---
**Author:** ![Hikmet](https://blenderartists.org/user_avatar/blenderartists.org/hikmet/32/774359_2.png) [@Hikmet](https://blenderartists.org/u/Hikmet)\ **Post date:** [June 16, 2022, 4:55pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/19 "2022-06-16T16:55:12Z")
So, what will you do when use fluid simulation? If you want realistic render, then you must consider real-life physics. ---
**Author:** ![SterlingRoth](https://blenderartists.org/user_avatar/blenderartists.org/sterlingroth/32/3107_2.png) [@SterlingRoth](https://blenderartists.org/u/SterlingRoth)\ **Post date:** [June 16, 2022, 4:56pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/20 "2022-06-16T16:56:08Z")
Animation is much more complicated, yes. For a still like the OP is asking for, the method outlined in that article is accurate to real-life physics. ---
**Author:** ![joseph](https://blenderartists.org/user_avatar/blenderartists.org/joseph/32/1433056_2.png) [@joseph](https://blenderartists.org/u/joseph)\ **Post date:** [June 16, 2022, 4:58pm UTC](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201/21 "2022-06-16T16:58:58Z")
While this discussion about rendering glass is both important and useful, the more recent part of it isn’t quite on topic. OP is asking for specific ways to improve their rendering results, so more generalized discussions about the technical minutiae of glass aren’t really applicable. That discussion could be moved to a different thread, for example, in #general-forums:blender-and-cg-discussions, and further discussion on this thread should probably relate specifically to OP’s case 🙂 [Next page](https://blenderartists.org/t/accurate-liquid-in-glass-rendering/1386201.md?page=2)