Creating Glass Materials in Blender: Glass BSDF and Principled BSDF

What will you learn in this guide?

When creating a glass look in Blender, you can focus on reflection and refraction with Glass BSDF, or use Principled BSDF to manage more surface properties in one place. This guide walks through the basic settings for both options, the parameters that change the appearance of glass, and some considerations when working in Cycles.

This isn’t a one-size-fits-all recipe for “correct glass”; it’s a workflow for experimenting with different surfaces, such as windows, display cases, glass partitions, and decorative coatings. Evaluate the result of each setting in the context of the scene’s lighting and surrounding objects.

Requirements

You’ll need to be able to create a material in Blender and work with shader nodes. The sources do not specify any particular compute type or external add-on as a requirement for using Glass BSDF or Principled BSDF. The guides also do not provide a Blender version number, so compatibility with a specific version cannot be guaranteed.

You’ll need to use Cycles to test the thin film effect; Blender’s documentation describes this feature as exclusive to Cycles. The guides do not specify a render engine restriction for the other glass settings covered here. Before you start, it helps to define the look you’re aiming for: a sharp, transparent windowpane doesn’t need the same roughness as a cloudy surface.

Creating a glass material step by step

1. Choose the right shader

You can start with Glass BSDF to create reflection and refraction behavior similar to glass. This shader handles both reflection at the surface and the transmission of refracted light. If you need to manage different properties—such as base color, metallic components, transmission, or a coating—in one node as part of a broader material setup, Principled BSDF is a good starting point.

If you want to compare the two approaches, test them on similar surfaces in the same scene. That way, you won’t need to change the scene lighting when you switch material nodes, making the visual differences easier to evaluate.

2. Set transmission in Principled BSDF

In Principled BSDF, Transmission Weight determines how the surface transitions from an opaque appearance to one that lets light pass through completely. For an initial test, increase this value and review the result; if you’re aiming for full light transmission, try a value of 1. Base Color sets the material’s base color and is used by different shader components.

IOR is the index of refraction that determines reflection and transmission behavior. Blender’s documentation notes that the default value of 1.5 for Principled BSDF approximately represents glass. Keeping this as your starting point and comparing the other settings first makes it easier to understand the effect of each change.

3. Control sharpness with Roughness

In Principled BSDF, Roughness affects how sharp reflection and transmission appear. A value of zero corresponds to sharp reflections; as the value increases, reflections become more diffuse. In Glass BSDF, the same setting controls the sharpness of refraction: refraction is sharp at zero and appears softer at higher values.

For sharp window glass, start with low values and check the surface in your scene. If you’re after a frosted or cloudy look, increase Roughness and compare the results. In both shaders, changing several parameters at once makes it harder to identify which one affected the result. Change one setting at a time for each test.

4. Review color and IOR in Glass BSDF

The Color input in Glass BSDF affects the surface color and the likelihood of light passing through at different wavelengths. Blender’s documentation specifically notes that pure white should be used for this input to achieve full transparency. IOR determines how much a ray changes direction as it passes through the surface. At a value of 1.0, rays continue without changing direction; higher values produce more pronounced refraction.

Here, too, start with low Roughness and then increase it to observe the difference in sharpness. If you change the glass color, keep in mind that color also affects light transmission. Review the result not only in the material preview but also in the scene where the material will be used.

5. Try Thin Film in Cycles

Thin Film simulates how a thin layer on top of a material interacts with light. It can produce angle-dependent coloration and can be used for looks such as an oil film, soap bubbles, or a glass coating. This option is exclusive to Cycles.

Film thickness is set in nanometers. At a value of 0, the simulation is off; the effect becomes stronger at approximately 100–1000 nanometers. The common IOR range for the film is 1.0 to approximately 2.0, and a value of 1.33 is given as a good approximation for water. The effect may disappear if the film IOR is set to 1.0 or to the IOR of the main material. So rather than adding Thin Film to every glass surface, consider whether angle-dependent color is actually needed in the design.

Common issues

Glass materials can produce image noise due to caustics. Since Cycles’ path-tracing calculations do not always produce these light concentrations cleanly, test the shadow side as well when you notice noise. Blender’s documentation notes that using Transparent BSDF for shadows alongside the glass shader can help reduce this issue. This approach is not guaranteed to eliminate noise in every scene, so verify the result in a render.

Another common mistake is trying to fix cloudy glass using only IOR. Roughness affects the sharpness of refraction in Glass BSDF and the appearance of reflection and transmission in Principled BSDF. Change parameters one at a time to identify which setting is causing the issue.

If you’re using bump or displacement on a glass surface, remember that the method you choose also affects the result. True displacement changes mesh points before rendering; it requires a densely subdivided mesh for the best quality and uses more memory. Bump Only affects normals without changing the actual surface; it uses less memory but provides an approximation, does not change the silhouette, and does not produce displacement-based self-shadowing. You can also combine the two methods.

Using this in an architectural visualization workflow

These settings are useful for architecture firms, interior designers, and visualization artists creating interior visualizations in Blender, when setting up windows, glass partitions, display cases, and coated surfaces. Principled BSDF brings properties such as transmission and roughness together in one shader, while Glass BSDF focuses on glass behavior. Teams using Cycles can also explore coating effects with Thin Film.

In practice, start with a simple surface and compare Roughness and IOR separately. If you see caustics-related noise, test the Transparent BSDF approach for shadows. When you need displacement for detail, consider the mesh density and memory requirements; when bump is sufficient, keep its silhouette and shadow limitations in mind. Since the sources do not provide specific hardware recommendations or performance measurements, no definitive conclusions about hardware selection can be drawn.

As a next step, create two test materials in the same scene lighting, one using Glass BSDF and the other Principled BSDF. Compare transmission and IOR first, then Roughness. If you need Thin Film, run this test in Cycles and evaluate the result under the angles and lighting conditions intended by the design.

Sources and license

This guide has been adapted into Turkish using the “Glass BSDF,” “Principled BSDF,” and “Material Settings” documents in the Blender Manual. All sources are provided under the CC BY-SA 4.0 license.