Help with Material Settings for Blue Glass Jar with Aluminum Lid

Question

I'm working on a scene in Blender where I've created a blue glass jar with an aluminum lid. Unfortunately, I can't get the material to look the way I want, matching my reference image. I've already experimented with different settings in the Shader Editor, but the result still doesn't look like the reference.

I've attached a few screenshots of my current material settings. My goal is to make the glass and aluminum look more realistic – I'm especially struggling with the reflections and transparency of the glass, as well as achieving a metallic look for the lid.

Here are some details about my setup:

• Glass Shader: I'm currently using Glass BSDF.
• Aluminum Shader: For the lid, I've set up Principled BSDF.

I'd really appreciate any tips on how to improve the realistic look. Maybe I'm also missing something with the lighting or render settings?

Reference picture

Glass shader settings

Aluminum shader settings

My workspace

Current render result

Answer 1

For the aluminum shader, I would not change a lot. In my opinion it is just a bit too "shiny", I would increase the Roughness more. So I did not bother to model a cap or any real top for the jar in my answer.

As a preliminary, in the following example renders I have these settings under Light Paths > Max Bounces in the Render Properties:

• Total: 64
• Glossy: 16
• Transmission: 64

These are the important ones for glass materials, the others are negligible (but of course they should not be 0, not even the Volume bounces if you go for a volumetric shader in the glass, but it's less important there as those bounces are used for Volume Scatter).

So, for the glass material: first of all, I know there are a lot of tutorials teaching to mix a Glass BSDF or a transmissive Principled BSDF with a Transparent BSDF. And in some cases this helps especially when you want sharp shadows inside a glass object etc. But for the most part, a simple Glass BSDF or Principled BSDF with a Transmission > Weight of 1 are completely sufficient.

Here an example, just a colorless (= full white) glass material. On the left with transparency mixed in like your example, on the right just the glass. By the way, I left the Roughness at 0 to match your setup, but personally I would never use it like that - no glass is perfectly smooth, I would rather use a value of 0.03 to 0.05 usually.

In my opinion the simple Glass BSDF looks even better, because it seems unrealistic that the jar does not throw a faint shadow on the plane below since glasses are not perfectly invisible to light.

So I'll go with the simple version for the rest of the explanations. Of course a Glass BSDF seems an obvious choice if you want to make a glass material. Another way would be to take a Principled BSDF with Transmission > Weight set to 1. If it looks darker, that's because the Base Color is a light grey with a value of 0.8 by default, not full white. So I change that first. Now comparing the Glass BSDF to the Principled BSDF, there seems to be no real difference between them:

However, you will notice a very big difference if you want a colored glass like your jar with a dark saturated blue for example. While the Principled BSDF gives the surface a specular layer which reflects without tint, the Glass BSDF has only reflections tinted by the glass color like a metallic surface and these mirror-like reflections are what your jar is missing:

To get something similar for the Glass BSDF you have to mix it with a Glossy BSDF, this mix should be angle dependent so a Fresnel node is a good choice here.

If you want to go with the Principled BSDF but the reflections are too strong for your taste, you are often told that lowering the Specular > IOR Level will reduce/remove the reflections. While this is true for dielectric (= non-metallic) opaque diffuse surfaces, this has no effect on the specularity of metallic and transmissive materials. So in order to reduce the reflections, you can lower the Specular > Tint color from full white to something darker, blueish:

The Volume Absorption node in your setup is not really needed. When you make the surface such a strong saturated color as if the glass is color-coated on the outside, the volumetric effect is hardly visible.

Yes, it is not just helpful but rather mandatory if you want to create something like solid-colored glass which is colored throughout the material, so that the color is more intense on thicker parts. For that I would use a white surface color or just a light color with low saturation and then a strong color and high density for the Volume Absorption node. The white or light blue surface color would also help with the Glass BSDF having better reflections without the need to mix with a Glossy BSDF.

Here is a comparison between different surface colors in the Glass BSDF and varying Density values in the Volume Absorption node. The surface color affects the reflections and of course the overall color, while the volume density influences how much the material thickness affects the color. Of course this can be done with a Principled BSDF as well.

To come to a close, to get more examples how the initially mentioned Max Bounces can be important to get good glass materials, read my answer to this question:

Grey artifacts in glass bottle

If you are not happy with a simple glass material and want to use Light Paths to mix in some transparency, I would not Add the Is Shadow Ray and Is Diffuse Ray together, but rather plug the Is Shadow Ray and the Diffuse Depth into a Math node set to Maximum to get a mix factor. This factor can also be multiplied by values between 0 and 1 to change the amount of transparency. More on this in my answer to this question:

Glass object's surface problem