Output and VFB Overview

When rendering in Rhino V-Ray utilizes a V-Ray specific frame buffer, sometimes called the VFB which has many advantages:

  • Allows you to view all render elements in a single window and switch between them easily;
  • Keeps the image in full 32-bit floating-point format;
  • Allows you to view the rendered channels individually.
  • Has the ability to link to PDplayer.
  • Allows you to make comparisons between two renders
  • Allows you to do some color correction

The V-Ray VFB also has some limitations, which are listed in the Notes section below.

Output Size

Override viewport - This option allows you to override the resolution that V-Ray obtains from the Rhino viewport resolution or custom resolution in the render settings locate in the Rhino Options.

Width - Sets the width of the rendering in the V-Ray frame buffer.

Height - Sets the height of the rendering in the V-Ray frame buffer.

Image aspect - Sets the proportional relationship between height and width of the rendering in the V-Ray frame buffer. The image aspect ratio can be locked and unlocked.

Pixel aspect ratio- specifies the pixel aspect for the rendered image in the V-Ray frame buffer. The pixel aspect ratio can be locked and unlocked.

Get view aspect - this option will calculate the image aspect ratio from the current resolution set in the render settings from the Rhino Options and then replace the current Image aspect with that value.

Render Output

Save render output - when this is on, V-Ray will automatically save the image rendered to the V-Ray frame buffer.

V-Ray Raw Image File

Render to VRimage - when this is on, V-Ray directly writes to disk the raw image data as it is being rendered. It does not store any data in the RAM, so this feature is very handy when rendering huge resolutions for preserving memory. If you wish to see what is being rendered, you can set the VFB mode to Generate preview. You can specify either a .vrimg or an .exr file for output:

  • If you specify a .vrimg extension, the resulting file can be viewed by converting the file to an OpenEXR file with the help of the vrimg2exr tool. The file contains all the render elements for the image.
  • If you specify an .exr extension, V-Ray will write out a tiled OpenEXR file that can be used directly by Rhino or other compositing applications. When you click the Browse button you can specify the file name.

VFB Mode - these options allow you to select different modes to conserve memory when rendering.

No Memory - this option will not create a V-Ray frame buffer in order to conserve as much memory as possible.

Full Memory - this option will create a V-Ray frame buffer and will use it to store color data that you can observe while rendering and afterwards. This is the default mode when rendering when you are not rendering to a V-Ray image file.

Preview - this will create a small preview of what is being rendered by V-Ray but in order to conserve memory V-Ray will only render a small image of what is being actually rendered. This will allow you to stop the renderer if there is anything that looks wrong.

VFB Toolbar

This part of the toolbar sets the currently selected channel, as well as the preview mode. Choose which channels to see with the help of the buttons. You can also view the rendered image in monochromatic mode.
When comparing two images using the A/B compare feature of the VFB History these buttons allow you to choose the direction of the A/B separation line.
This will save the current frame data to a file.You can turn this on and of on-the-fly while rendering.
Opens a .vrimg file to be previewed in the V-Ray VFB
Clears the contents of the frame buffer. Sometimes helpful when starting a new render to prevent confusion with the previous image
This will create a 3ds Max virtual frame buffer copy of the current V-Ray frame buffer.You can turn this on and of on-the-fly while rendering.
This will force V-Ray to render the closest bucket found to the mouse pointer. Drag the mouse over the V-Ray frame buffer while rendering to see which buckets are rendered first. You can turn this on and of on-the-fly while rendering.
This option allows you to render regions in the V-Ray VFB
Links the V-Ray VFB to Pdplayer
This will open the color corrections dialog which will let you define color corrections of various color channels. It will also show the histogram of the currently contained image data in the buffer. Click and drag your mid-button in the histogram to interactively scale the preview.
Forces color clamping in the V-Ray VFB
Displays the clamped colors in the V-Ray VFB
This open permanently the info dialog which will give you information about the pixel you right-click the mouse pointer on. If you right-click the mouse pointer over a pixel without turning this setting on - then you will see the info dialog only while your mouse button is down
Enables the levels color corrections
Enables the color curve corrections
Enables the exposure corrections
Displays the image in sRGB color space
Enables the look up table
Shows the V-Ray VFB history
Enables the V-Ray lens effects
Enables the pixel aspect ratio
Enables the red/cyan stereoscopic view
Enables the green/magenta stereoscopic view

VFB History

The V-Ray VFB allows the user to keep a history of previously rendered images. The images are stored as .vrimg files on a location specified by the user. In addition to keeping history this feature allows the user to set A and B image and compare them inside the VFB.

Enable VFB history - enables the V-Ray VFB history

Options - brings out the VFB history options which allow the user to specify the location where the history will be saved and the amount of disk space available

Save - saves the current image from the VFB to the render history

Load - loads the image selected in the Render history to the VFB

Remove - removes the selected image from the render history

Clear - clears the render history

Set A - sets the currently selected image as image A for A/B comparison in the VFB

Set B - sets the currently selected image as image B for A/B comparison in the VFB

VFB Shortcuts

Here is the list of shortcuts you can use to navigate through the VFB image. Please note that VFB window must have the current focus for the shortcuts to have effect:

CTRL+LeftClick, CTRL+RightClickZoom in/Zoom out
Roll the mouse-rollon button up/downZoom in/Zoom out
Double-click LeftButtonZoom to 100%
RightClickShow the info dialog with the properties of the last pixel clicked. In order to see the info non-stop - turn on the info dialog button 
MidButton draggingview pan (hand tool)
+ / -Zoom in/Zoom out
*Zoom to 100%
Arrow keysPan left, up, right, down

Frame Stamp

The frame stamp is a convenient way to put some short text over the rendered images. It can be useful in many ways - for example, in network rendering, to quickly determine which frames were rendered by which machine. The frame stamp is one line of text, which appears at the bottom of the image.

Checkbox - turns the frame stamp on and off.

Edit box - here you enter the text you wish to appear in the images. You can also use some special keywords, all of which begin with the percent symbol (%). The keywords are replaced by V-Ray with the corresponding value:

vraycorethe current version of the V-Ray core
rendertimethe render time for the current frame
numProcessorsthe number of processors that the computer has available
datethe current system date
timethe current system time
amountPhysicalRAMthe amount of physical memory (in KBytes) installed on the system
amountVirtualRAMthe amount of virtual memory (in KBytes) available on the system
osDescthe operating system installed on the system

* An intersectable primitive is a primitive that provides a direct method for intersection with a ray (such as a triangle, the infinite plane generated by a VRayPlane, etc). Most often, the number of these primitives is the same as the number of triangles (faces) processed by V-Ray for the current frame. Note that this may be different from the total number of triangles in the scene. With the dynamic raycaster, only geometry that is actually needed is generated and accounted for. Geometry that is not generated is not included in this count.

Font - this button allows you to choose a font and font attributes for the text in the frame stamp.

Full width - when this option is checked, the frame stamp will take the whole width of the image, otherwise the stamp will be only as wide as the text is.

Justify - specifies the position of the stamp:

  • Left - the stamp is placed on the left of the image.
  • Center - the stamp is centered.
  • Right - the stamp is placed on the right side of the image.



  • The OpenEXR file format is an open file format for high dynamic range images originally developed by Industrial Light and Magic. The official site of the OpenEXR file format is http://www.openexr.com/