Every Trick for Shading Glass in Eevee - Fundamentals of Blender Materials & Shading (Bonus Video)

Jonathan Lampell from cgcookie.com introduces the challenges of creating realistic glass materials in Blender's Eevee render engine, which lacks the ray-tracing features of Cycles. He explains the limitations of the default glass BSDF, such as excessive distortion and the assumption of solid objects, which can distort the appearance of objects with holes or gaps. Lampell outlines the process of adjusting the index of refraction (IOR) and refraction depth to achieve a more realistic effect, while acknowledging the need to compromise on physical accuracy for visual appeal. He also discusses the inability to see through refractive objects in Eevee and introduces his custom shader designed to address these issues.

The tutorial delves into advanced material settings required for the custom glass shader, including turning off backface culling to preserve reflections and using alpha hashed blend mode for better layering of transparent objects. Lampell recommends increasing render samples for noise reduction and introduces the denoise node in the compositor. He then explains the shader's inner workings, focusing on the use of transparency and refraction to create glass, employing a mix shader to combine these effects and the addition of Fresnel for a more natural appearance. The summary also touches on the limitations of refraction and the creative use of layer weight nodes to achieve a gradual transition.

Lampell discusses the addition of dispersion to the glass shader, inspired by a video from Grant Wilk, to create a more realistic chromatic effect. He describes the process of separating RGB colors and applying refraction shaders to each channel, then mixing them based on Fresnel for reflections. To avoid a 'double-walled' effect, he introduces a method to enhance the refraction at the edges of objects. The tutorial also covers the creation of transparent shadows by combining the results of transparent and refractive materials based on shadow rays, thus achieving a more convincing glass material.

This section focuses on the fine-tuning of the glass shader's controls for user-friendliness. Lampell explains the various nodes and settings that allow artists to adjust the color, reflection tint, alpha hash color fix, reflection brightness, roughness, and inner refraction to achieve the desired look. He also introduces an edge refraction control that can be adjusted to prevent a double vision effect and discusses the use of absorption to simulate light penetration and scattering within the material, providing a more dynamic and realistic appearance.

The tutorial explores the implementation of caustics and absorption effects in the glass shader. Lampell credits other creators for their influence on his approach and suggests checking out their work for additional insights. He demonstrates how to create caustics using spotlights and adjusting their properties to project light through transparent shadows onto surfaces. The absorption effect is achieved by blending a mixture of diffuse and translucent materials based on a gradient texture that can be manipulated for different absorption patterns and colors, adding a layer of realism to the glass material.

Lampell addresses the issue of absorption effects appearing in the wrong location on an object by adjusting the texture space and mesh data properties. He explains how to change the gradient's center by manipulating the location along the x-axis and discusses alternative methods such as using nodes for more precise control. The summary also covers the process of combining various nodes to create a shader that respects light changes and can be adapted to different materials, concluding with the availability of the shader for download and further learning resources.

In the final paragraph, Lampell summarizes the glass shading techniques covered in the tutorial and invites viewers to download the custom glass shader node for immediate use. He also promotes his new course on cgcookie.com, which provides foundational knowledge on materials and shading in Blender, including a simplified glass shader build and an overview of shader nodes and settings for both Cycles and Eevee render engines. The paragraph concludes with an invitation to visit cgcookie.com for more learning opportunities.