• This lesson will take you through the basics of the V-Ray VFB window.
  • This lesson topic is approximately 30 minutes in length.
  • Lesson covers all 3 Learning Cycles for the Lesson Topic – Lecture, Demonstration, and Activity.
  • Learning Outcomes: You will be able to navigate around the V-Ray Virtual Frame Buffer window and how to use the Color Correction and Lens Effects tools within the VFB.


Available Materials


Goal – This lesson will give you a general overview of the V-Ray Frame Buffer and teach you how to use it efficiently.

Objective – We will go through the process of rendering a scene with V-Ray and how to view/adjust it properly within the VFB window          

Outcome – You will know how to view your render outputs correctly within Maya and how to make adjustments directly to your images with the tools provided by V-Ray



Available materials

To set up the lesson follow the links below and download all available materials:

Lesson plan download
Presentation (Lecture) download
Demonstration tutorial download       
Scenes & Assets download


1. Terminology

The V-Ray VFB is the proper way to view V-Ray's render outputs
  • Virtual Frame Buffer – The VFB is the window that we use to view our renders.
  • Render History – Previous render outputs can be saved and compared to.
  • Color Corrections – Adjustments can be made to our rendered images directly from the VFB window
  • Lens Effects – Simulates bloom and glare lens effects on your rendered images in the VFB window

2. Launching

  • The VFB can be launched from the Render Settings, Output tab or from the V-Ray Shelf
    • If Use V-Ray VFB is checked, the V-Ray VFB will launch when Rendering the current View or starting an IPR (RT) Render







3. Overview

 V-Ray allows you to render to a V-Ray specific frame buffer, which has some additional capabilities

  • View all render elements in a single window and switch between them easily
  • Keeps the image in full 32-bit floating-point format
  • Perform color corrections on the rendered image
  • Can store a list of recently rendered images and switch between them easily
  • Apply lens effects to the rendered image



4. Toolbars

 а) Top window tools

  • Render Element dropdown selection
  • R, G, B, and A channel isolation buttons
  • Monochrome view
  • Save current channel
  • Load image into buffer
  • Clear (or remove) an image from buffer
  • Duplicate to Maya Frame Buffer
  • Track mouse while rendering
  • Render selected region
  • Link V-Ray VFB to PDplayer
  • Swap A and B images
  • Enable Comparison from images in history
  • Stop current render
  • Repeat last render



b) Bottom window tools

  • Color Correction window
  • Force Color clamping in VFB
  • Info dialogue (for pixel details)
  • Hue/Saturation color corrections
  • Color Balance color corrections
  • Levels color corrections
  • Curve color corrections
  • Exposure corrections
  • Use Background image
  • Display image in sRGB
  • Toggle Look Up Table from Color Corrections
  • VFB History window
  • Enable visualization of pixel aspect ratio
  • Toggle stereoscopic preview
  • Lens Effects window



c) Stamp tools
  • Toggle stamp tools buttons
  • Apply rendering metadata
  • Stamp Variables window
  • Align stamp options
  • Change stamp placement
  • Choose Font window

5. Tool Highlights

 а) Render Region

  • Similar to version in Maya Render View




b) Track mouse while rendering
  • Will follow the position of the mouse while rendering and update the buckets underneath the cursor



c) RGB Channels
  • Solo the different color channels
  • Alpha channel button as well





d) Render Elements dropdown
  • Displays Render Elements (AOVs) chosen in Render Settings





6. Color Corrections

 V-Ray frame buffer allows various color corrections to be applied to the image

  • Some types of color corrections are applied to just the view, and not saved to the image - sRGB, LUT, OCIO, ICC color corrections
  • Other types of color corrections made here are saved to the image when saved through the VFB







a) Exposure

  • Allows exposure and contrast adjustments
  • Positive Contrast values push the colors away from the medium gray value to increase image contrast, while negative values push the colors closer to medium grey



b) White Balance
  • Correct the colors in the image so that objects that are white appear white in the final image



c) Hue/Saturation
  • Moving the Hue slider changes the overall hue of the image colors
  • Higher Lightness values add white to the image, whereas lower values subtract white from the image



d) Color Balance
  • Adjusts the overall color tone of the image, as well as the tone of the dark (shadow), medium, and bright (highlight) colors



e) Curve
  • Allows remapping of the image colors with a Bezier curve
  • Also allows saving and loading .acv curve files from Adobe Photoshop



f) Saving and Loading Presets

  • Global level save – covers all CC adjustments
  • Or save settings per section



7. VFB History

 Keeps a list of previously rendered images

а) Saving renders

  • The images are stored as .vrimg files at the location specified
  • All renders can be automatically saved if History Settings is configured that way





b) Comparing renders

  • Set previous render as “A” frame
  • Change comparison from vertical to horizontal division
  • Outside A/B compare mode, double-click renders in History window to load into VFB 



8. Lens Effects

 A render effect plugin used to simulate bloom and glare lens effects by filtering the rendered image with a filter kernel

  • The options can be accessed through the V-Ray frame buffer with the Open Lens Effects settings button



a) Bloom Effect
  • Fill edges – adds pixel data outside the edges of the original image (will remove the darkening around the edges)
  • Mode – determines if the bloom will be applied to the RGB image, stored in a separate render element, or both
  • Weight – specifies the strength of the interpolation between the filtered image and the original image
  • Size – specifies the size of the filter as percentage of the image's width
  • Shape – specifies the fall off of the filter
b) Bloom Mask
  • Section controls where the bloom effect will be applied to the image


c) Glare Effect

  • Type – specifies how the glare is computed. The possible values are:
    • From image – takes the image specified in Glare Image as filter kernel
    • From render camera – takes the necessary parameters from the camera used to perform the rendering and automatically generates the filter kernel
    • From camera parameters – takes the camera parameters specified in the VRayLensEffects render effect itself and automatically generates the filter kernel
  • Glare Image – path to the filter kernel. Available if From Image option is selected (you can create filters using the Filter generator tool which comes with the V-Ray for Maya installation)
  • Turn on diffraction – produces colored patterns in the glare
  • Use obstacle image – draws the aperture shape as wall as any dirt or scratches on the lens which will affect the glareShape (specifies the falloff of the filter)



9. Stamp Controls

  • Toggle Stamp controls from bottom right corner of VFB
  • Apply Stamp with rendering metadata to rendered image
  • Stamp can be aligned with Left, Center, or Right justification
  • Stamp can be located at the Top or Bottom of the render
  • The font used for the Stamp can also be changed

10. Stamp Variables

  • Stamp variables can be typed directly into the stamp textbox with a % symbol before and separated with a | symbol
    • Example: %rendertime | %frame | %camera
  • Can also use the Stamp variable window to select/highlight variables and clip on the Copy to stamp button to add them to the stamp textbox



11. Lecture Conclusion

a) VFB Toolbars
Quick access to tools from the VFB window
b) Render History
Not just to go back to the past, but a comparison tool
c) Color Corrections
Access to almost everything that’s not a render setting                       
d) Lens Effects                                                                             
Bloom and Glare Effects



a) VFB Toolbars

Quick access to tools from the VFB window
b) Render History
Not just to go back to the past, but a comparison tool
c) Color Corrections
Access to almost everything that’s not a render setting                       
d) Lens Effects                                                                             
Bloom and Glare Effects



Time to see it work! Demonstration Cycle!

Watch while I demonstrate the different features of the V-Ray VFB window.




Time to do it yourself! 

Use the provided scene file to work through the activity as you have seen me demonstrate.
We have also provided a final scene for your reference.