# Transparent and translucent materials

Refraction is when light bends as it passes from one material ('medium') into another. Your eye can see refraction only through a transparent material, because most light is absorbed or reflected in opaque materials.

| Topic                                   | Description |
|-----------------------------------------|-------------|
| [Understand refraction](understand-refraction.md) | Gain a basic understanding of what refraction is and how it works in HDRP. |
| [Create a refractive material](create-a-refractive-material.md) | How to enable and configure refraction in HDRP.|
| [Refraction models](refraction-models.md) | Learn about the effects of the refraction models HDRP includes.|
| [How HDRP calculates color for reflection and refraction](how-hdrp-calculates-color-for-reflection-and-refraction.md) | Learn about the data sources HDRP uses to render realistic refraction and reflection techniques. |