Please note that this documentation space offers information for V-Ray 3.6! For most up-to-date documentation, refer to V-Ray Next for Modo help.

The Light Select Render Element stores direct lighting information from user-selected lights in the scene. 

 

Page Contents

 

Overview


The Light Select Render Element represents the lighting contribution from one or more user-selected lights in the scene. Each Light Select channel can output the selected lights' raw, diffuse, or specular contributions to the illumination, or the overall (direct illumination) light contribution. Using the Full light mode, you can esstiantially create a Beauty render for just the included light(s) a part of the Light Select pass. When multiple lights are selected for one Light Select Render Element, all contributions from those lights are combined into that one render element. Multiple V-Ray Light Select passes can be rendered for a single scene, and lights may be included in more than one V-Ray Light Select pass.

This element is similar to the  Light Render Element. However, the Light element combines the effect of all lights in the scene while the Light Select element allows for just a user-selected light or set of lights to be broken out; showing their own individual effect(s) on the scene's illumination. By using these render elements, specific lights in the resulting render can be adjusted (color, temperature, brightness, etc.) in a composite without the need for re-rendering.

For example, by generating a Light Select element for all of the backlights in a scene, an artist may adjust the backlighting of the rendered scene easily in the composite, without affecting the rest of the scene's illumination.

Note: Specific objects can be excluded from this Render Element by disabling the Generate Render Elements option in the V-Ray Object Properties extra package for the selected object(s).

 




 UI Path: ||Shading viewport|| > Shader Tree > Add Layer button > V-Ray Render Elements > V-Ray Light Select



Attributes 


The parameters for this render element appear in the Properties tab when V-Ray Light Select is selected in Modo's Shading tree.

 

 

 

Name – Sets a custom name for the render element.

Included Lights – Selects the light which will be included in the render element.

Include Child Items – When enabled, also includes all child lights of the selected one.

Direct illumination – When enabled, lighting within the V-Ray Light Select element behaves as normal and contains diffuse and specular information.

Direct raw – Lighting within the V-Ray Light Select element behaves as a raw render element.

Direct diffuse – Lights within the V-Ray Light Select element output only their diffuse contribution and contain no specular information.

Direct specular – Lights within the V-Ray Light Select element output only their specular contribution and contain no diffuse information.

Full – Lights within the VRayLightSelect element provide full output for all information available in the scene such as GI, SSS, reflection, refraction, etc.

Apply color mapping – Applies the color mapping options specified in the Color mapping rollout of the Main Render Settings in the Render Settings window to this render element. This option is enabled by default.

Consider for Anti-Aliasing – When enabled, anti-aliasing will be used where possible.

 

 

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 Top, Back, Left, and Right lights have been assigned a V-Ray Light Select render element with the Type set to Full.

Next, the Top and Back lights have been 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 each light's diffuse and specular contributions. All other lights in the scene have had their Type set to Direct Illumination.

The scene used for the images below uses quite a few lights. There are 4 area lights, a top light, a back light, a left light, and right light as well as a Dome light with an indoor factory HDR as its Dome light texture. As well as these, there are many Photometric IES lights in the environment and each space ship in the scene also has 3 Sphere Lights. The examples below show how several Light Select Render Elements can be combined to give the same result as the Light render element, and combined with the Global Illumination render element to give the equivalent of the  Total Light render element. This gives a fine level of control in the composite to change things such as the intensity or color tinting of only some lights at a time.

 

V-Ray Light Select Render Examples


 

 


Light Select Final Render

 


Light Select Key Light

 

 

 


Light Select RIM Light

 


Light Select Details_2

 

 

 


Light Select Details

 


Light Select Top Light

 

 

 

 

Light Select Blend Result

 

 

Compositing Equation


The following diagram shows the compositing formula to recreate all the light in a scene in its most basic form using discrete Light Select Render elements. This can happen only when each light in the scene is accounted for in only one V-Ray Light Select element for a particular mode. If any light is used in more than one V-Ray Light Select pass, this equation will result in a brighter lighting than intended, because duplicated lights in Light Select Render Elements will contribute lighting more than once.

 

For V-Ray Light Select to work correctly, all enabled lights need to be accounted for in a Light Select Render Element.

When the V-Ray Light Select Render Element is set to Direct illumination type, the sum of all the V-Ray Light Select nodes replaces both the Light and the  Specular render elements in the  Back to Beauty composite.

When the V-Ray Light Select Render Element is set to Direct diffuse type, the sum of all the V-Ray Light Select nodes replaces the Light render element in the Back to Beauty composite.

When the V-Ray Light Select Render Element is set to Direct raw or Direct specular type, the sum of all the V-Ray Light Select nodes replaces their respective render elements in the Back to Beauty composite.


Notes


  • When using V-Ray Light Select, a good practice is to have one V-Ray Light Select pass for each light source in your scene. This way the Light element can be recreated from them, and adjusted as needed while compositing without re-rendering.

  • If the V-Ray 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.