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title: "Lens Effects Filter Generator"
canonical: "https://documentation.chaos.com/space/VRAY4TOOLS/117637135/Lens%20Effects%20Filter%20Generator"
format: markdown
---
This page contains information about V-Ray's standalone Lens Effects Filter Generator. Overview The Filter Generator is a tool to create HDR filter kernels for use in the V-Ray Frame Buffer Lens Effects'  Glare Image  parameter. The V-Ray Lens Effects Filter Generator is based largely on the model presented in    Physically-Based Glare Effects for Digital Images . For a complete list of references, please see the  References  section. Location The Filter Generator utility is included with the V-Ray installation. See its location according to your host application: V-Ray for Maya V-Ray for Houdini V-Ray for Revit V-Ray for Unreal V-Ray for Cinema 4D V-Ray for SketchUp V-Ray for Rhino File Options The file menu shows options for saving and loading presets and exporting the final filter kernel. Radial Symmetric Pattern Parameters The Radial Symmetric Pattern parameters control the scale of the overall Lens Filter. Shape  – Adjusts the size of the pattern. Corona Flare Lines Pattern Parameters The Corona Flare Pattern parameters control the amount of rays emanating from the light source. Diametric   – When enabled, mirrors the pattern across the center. Radius  – Controls the size of the pattern radius. Number Of Lines  – Controls the number of lines in the pattern. Example: Corona Flare Lines Pattern This example demonstrates how different values of the  Number of Lines  parameter affect the lens effect. Increasing the Number of Lines value produces more rays emanating from the light source, while decreasing it lowers the number of rays. The last image also has the  Diametric  parameter enabled, which mirrors the ray pattern across the center (thus producing symmetrical flares). Number Of Lines  = 100,  Diametric  is off Number Of Lines  = 20,  Diametric  is off Number Of Lines  = 5,  Diametric  is off Number Of Lines  = 5,  Diametric  is on Special Flare Lines Pattern Parameters The Special Flare Pattern parameters control the pattern of the Special Flares Lines. Ray Pattern Dropdown   – Determines the number of Ray groups. Radius   – Scale of the Special Flares Lines Lens kernel in Percent. Number of Lines   – Determines the amount of lines used in each ray pattern. Range   – Controls the spread of the Ray Pattern.  Rotation  – Rotates the entire Special Flare Lines Pattern in degrees. Example: Special Flare Lines Pattern  This example shows the effect of  Range  and  Ray Pattern  parameters on the lens appearance. The  Number of Lines  is set to 10 for all images. Range  = 10,  Ray Pattern  = 2 Range  = 10,  Ray Pattern  = 4 Range  = 10,  Ray Pattern  = 6 Range  = 10,  Ray Pattern  = 8 Lenticular Halo Parameters The Lenticular Halo parameters control the bounds of the halo. Inner Radius  – Sets the inner bounds of the Lenticular Halo Outer Radius  – Sets the outer bounds of the Lenticular Halo. Example: Lenticular Halo This example shows how changing the inner and outer bounds values affects the Lenticular Halo. The  Inner Radius  is set to 20 for all images. Outer Radius  = 40 Outer Radius  = 60 Outer Radius  = 120 Mix Parameters The Mix parameters control how the Lens Parameters mix together into the final Filter kernel. Pattern 1  – Sets the percentage Radial Symmetric Pattern 1 is mixed with the final Filter kernel. Pattern 2  – Sets the percentage Radial Symmetric Pattern 2 is mixed with the final Filter kernel. Halo   – Sets the percentage the Lenticular Halo has on the final Filter kernel. Aspect  – Determines the Aspect Ratio of the final Filter kernel. Apply Corona Flare Pattern   – Enables kernel filtering with the Corona Flare Pattern. Apply Special Flare Pattern  – Enables kernel filtering with the Special Flare Pattern. Example: Special Flare Pattern The following examples show how lens parameters can be mixed together to achieve a final filter kernel. Apply Corona Flare Pattern  is on,  Halo  = 0,  Diametric  is on,  Number of Lines  = 5 Apply Special Flare Pattern  is on,  Halo  = 0,  Number of Lines  = 10,  Range  = 40,  Ray Pattern  = 6 Apply Corona Flare Pattern  is on,  Apply Special Flare Pattern  is on,  Halo  = 0,  Number of Lines  = 10,  Range  = 40,  Ray Pattern  = 6 Apply Corona Flare Pattern  is on,  Apply Special Flare Pattern  is on,  Halo  = 35,  Number of Lines  = 10,  Range  = 40,  Ray Pattern  = 6 Apply Corona Flare Pattern  is on,  Apply Special Flare Pattern  is on,  Halo  = 70  Number of Lines  = 10,  Range  = 40,  Ray Pattern  = 6 References Here is a list of references about the V-Ray Sun and Sky implementation, as well as general information about the illumination of the Sun. G. Spencer, P. Shirley, K. Zimmerman, D.P. Greenberg  Physically-Based Glare Effects for Digital Images. ;  An online version can be found at  https://www.graphics.cornell.edu/pubs/1995/SSZG95.pdf . This paper is the base for the V-Ray Lens Effects Filter Generator.