How Do You Reflect Light in Blender?

Creating reflections in Blender primarily involves using the right material shaders for your objects. Reflections are a key visual element that adds realism and depth to 3D scenes.

In Blender, the behavior of a surface, including how it reflects light, is determined by the shader assigned to its material. Different shaders simulate different types of surfaces.

Understanding Shaders for Reflection

According to the provided reference:

• Diffuse shaders simulate rough, non-reflective surfaces (like matte paint or paper). They have zero reflections.
• To get reflections on a surface that might also have diffuse properties, traditionally you would need to mix a Diffuse shader with a Glossy shader. The Glossy shader is specifically designed to create reflective surfaces.

However, the reference highlights a more modern and streamlined approach:

• The Principled BSDF shader is described as a simpler and more realistic way to handle reflections and other surface properties.

Using the Principled BSDF Shader (Recommended Method)

The Principled BSDF shader is Blender's all-in-one, physically based shader. It incorporates properties like diffuse, specular (reflection strength), roughness (clarity of reflection), metallicness, and more into a single node.

To use it for creating reflections:

1. Select the object you want to make reflective.
2. Go to the Shading workspace or the Shader Editor.
3. Create a new material or select an existing one.
4. Ensure the main shader node connected to the Material Output is a Principled BSDF node.
5. To apply textures (like a color map): just add a principled shader node and connect the texture to it the way you connected it to the diffuse. Connect the Color output of your image texture node to the Base Color input of the Principled BSDF.
6. Control the reflection using the parameters within the Principled BSDF node:
   • Specular: Controls the strength of the reflection.
   • Roughness: Controls how sharp or blurry the reflections are. A value of 0 results in mirror-like reflections, while a value closer to 1 makes reflections very blurry or non-existent.
   • Metallic: For metallic surfaces (like polished metal), set this value towards 1. This fundamentally changes how the surface reflects light (metallic surfaces reflect the color of the light source directly, while non-metals reflect a desaturated version).

Using the Principled BSDF is generally preferred because it simplifies node setups and provides more physically accurate results out of the box, combining multiple surface properties (including reflection) into a single node.

Older Method: Mixing Diffuse and Glossy Shaders

While the Principled BSDF is recommended, you can still achieve reflections by mixing a Diffuse and a Glossy shader. This method is explicitly mentioned in the reference as requiring a mix because diffuse shaders have zero reflections.

1. Add a Diffuse BSDF node and a Glossy BSDF node.
2. Add a Mix Shader node.
3. Connect the Diffuse BSDF output to one input of the Mix Shader.
4. Connect the Glossy BSDF output to the other input of the Mix Shader.
5. Connect the Mix Shader output to the Material Output node.
6. Use the Factor input of the Mix Shader to control the blend between the diffuse and glossy properties. A factor of 0 means only diffuse is visible, a factor of 1 means only glossy is visible, and values in between mix them.
7. Adjust the Roughness on the Glossy BSDF to control the sharpness of the reflections.

In summary, to reflect light in Blender, you primarily use shaders like the Principled BSDF or a Glossy BSDF, adjusting parameters like Roughness and Specular (or Metallic) to control the reflection's appearance. The Principled BSDF is the modern and recommended approach.