--- title: "V-Ray Light Select" canonical: "https://documentation.chaos.com/space/VRAYHOUDINI/113279518/V-Ray%20Light%20Select" format: markdown --- The Light Select Render Element stores direct lighting information from user-selected lights in the scene.  ## **Overview** --- ## **Attributes** --- ## **Common Use: Changing Lighting in Composite** --- Below is an example of how to use the Light Select Render Element in a composite. For this example, the Dome Light is assigned two V-Ray Light Select render elements: The first element's **Type** is set to **Direct Diffuse**, and the second element's **Type** is set to **Direct Specular**. This gives a finer degree of control to allow separate tuning of the light's diffuse and specular contributions. In addition, the light is rendered with a third element with the **Type** set to **Full**. --- ### **Example: Compositing** V-Ray Light Select is useful for editing the lights in a scene using a compositing or editing program. See the Beauty element before and after compositing. ## **Compositing Equation** --- The following diagram shows the compositing formula to recreate all the scene Lighting from light sources when each light in the scene is accounted for in exactly one V-Ray Light Select render element in **Direct Diffuse** type. The diagram above illustrates that the sum of all V-Ray Light Select Render Element set to **Direct Diffuse** type represents the V-Ray Direct Light render element which can be used in the Back to Beauty composite. For the above equation to work correctly, all enabled lights need to be accounted exactly once in the V-Ray Light Select render elements. This happens with either specifying each light in a separate element, or combining them in a practical manner in several elements and avoiding repetitions. When the Light Select Render Element is set to **Direct Illumination** type, the sum of all the Light Select nodes replaces both [Direct Light](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113280982) and [Specular](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113279768) in the [Back to Beauty](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113281534) composite. When the Light Select Render Element is set to **Direct Diffuse** type, the sum of all the Light Select nodes replaces Direct Light in the Back to Beauty composite. Note that [BRDFAlSurface](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113280207) Shader with sss_mix value other than the default 0, doesn't fit this equation. When the Light Select Render Element is set to **Direct Raw** or **Direct Specular **type, the sum of all the Light Select nodes replaces their respective render elements in the Back to Beauty composite. Note that Direct Raw type replaces the [Raw Direct Light](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113280980) render element if GI is disabled and there are no dome lights in use. When the Light Select Render Element is set to **Indirect **type, the sum of all Light Select nodes replaces all the [Global Illumination](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113280985), [Reflection](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113279771) and [Refraction](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113279770) in the Back to Beauty composite. Note that the Indirect Diffuse type and the Indirect Specular type combined result in Indirect type. When the Light Select Render Element is set to **Indirect Diffuse** type, the sum of all the Light Select nodes replaces Global Illumination in the Back to Beauty composite. When the Light Select Render Element is set to **Indirect Specular** type, the sum of all the Light Select nodes replaces Reflection in the Back to Beauty composite. When the Light Select Render Element is set to **Full** type, the sum of all Light Select nodes replaces the [Beauty](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113281534) pass. Caustics are not included in the calculation of Light Select Render Element. ** ** ## **Notes** --- - When using Light Select, a good practice is to have one Light Select pass for each light source in your scene. This way the Lighting element can be recreated from them, and adjusted as needed while compositing without re-rendering. - If the Light Select element **Type** is set to **Direct Illumination**, the specular contribution is added to the render element. While this is perfect for simple compositing, a better workflow is for each light to be selected for two Light Select Render Elements, one with its **Type** set to **Direct Diffuse** and another with its **Type** set to **Direct Specular**. In this way, the specular and diffuse lighting can both be controlled independently at a composite level. - If the light source is wrong or missing, the Light Select will not be rendered.