This page contains information for controlling the V-Ray Frame Buffer through environment variables and MaxScript.

Overview

The V-Ray Frame Buffer can be controlled programmatically in two ways: the first is by using MaxScript commands and the second, by using various environment variables.

From MaxScript

The vfbControl() MaxScript function modifies the various aspects of the VFB. These commands can be used in the MAXScript Listener or in an executable script. Commands follow this structure:

vfbControl (parameter) 
vfbControl (parameter) (argument)

For example, to turn off the red channel in the VFB, type

vfbControl #red false

To see a list of available options, type one of the following:

vfbControl()
vfbControl #help

Global VFB function	Description
vrayVFBGetRegionEnabled()	Returns whether region rendering in the V-Ray VFB is enabled (true) or disabled (false).
vrayVFBGetRegion()	Returns an array with four integer elements, representing the pixel coordinates of the VFB render region (left, top, right, bottom). The left and top coordinates are included in the region, the right and bottom one are not.
vrayVFBSetRegionEnabled true\|false	Turns on or off the VFB region render option.
vrayVFBSetRegion left top right bottom	Sets the VFB render region to the specified coordinates.
vrayVFBGetNumChannels()	Returns the number of channels (render elements) in the V-Ray VFB. This will return 0 if the VFB is not initialized or does not store any data.
vrayVFBGetChannelName i	Return the name of the i-th channel. Indexes start from 1.
vrayVFBGetChannelType i	Returns the storage type of the i-th channel. Indexes start from 1. The return value specifies the type of data for each pixel in the given channel: 0 - the index is not valid or the VFB does not store an image; 1 - a single floating-point number (this is used, for example, for the z-depth channels); 2 - three floating-point numbers (this is used for regular color channels); 3 - two floating-point numbers; 4 - a single integer number (used, for example, by the render ID and material ID elements); 5 - three signed floating-point numbers (this is used, for example, for normals and world position channels).
vrayVFBGetChannelAlias i	Returns the alias for the i-th channel. Indexes start from 1. See the RegionChannelAlias enum in the file "pixelbuffer.h" from the V-Ray SDK.
vrayVFBGetChannelBitmap i	Returns the contents of the specified channel as a 3ds Max bitmap. Indexes start from 1. This will return undefined if the channel index is not valid or the VFB does not contain any data.
vfbControl()	Allows control over the various aspects of the V-Ray VFB. Type vfbControl() for a list of available parameters, or for more details see the Controlling the VFB Programmatically page.
vfbControl #show [true/false]	Opens (true) or Closes (false) the VFB window or returns its current display state if called without a value.

Parameter Tables

Here are some guidelines for using MaxScript:

Arguments listed as Boolean can only receive true/false values. These options turn a feature on (true) or off (false).
Remember that float values include a decimal while integers do not. This means that integers can be used when a float is required, but float values cannot be used where integers are required.
String values must be enclosed in double quotes.
Available values from enumerated lists are presented with a pipe (|) separator. For example, 0 | 1 | 2 means the argument value can only be a 0, 1, or 2. String values of this argument type are input with quote marks. For example, #setregion "reset"
Successfully loading a file or setting a numerical value implicitly enables the corresponding option. For example, using #setregion to set a region for rendering automatically turns on region rendering. If you want to disable a feature, do it after running the load/set command.
Many commands will return the current values for the parameter when used without arguments. This feature has been enabled for all commands for which it makes sense to do so.

VFB Toolbar Options

Parameter	Description	Arguments	Examples
#help	Displays options for the vfbControl command	None
#show	Opens (true) or closes (false) the VFB window or returns its current display state if called without a value	Boolean
#rgb #red #green #blue #alpha #mono	Enables/disables the corresponding VFB toolbar feature	Boolean	vfbControl #alpha true
#trackmouse	Enables/disables the Track mouse while rendering feature	Boolean
#linkpdp	Enables/disables the Link VFB to PDPlayer feature	Boolean
#swapab	Enables/disables the Swap A/B feature	Boolean
#setcompareab	Enables/disables Compare horizontal and Compare vertical features	"h" \| "hor" \| "horizontal" "v" \| "ver" \| "vertical"	vfbControl #setcompareab "h"
#loadimage	Loads the specified image in VFB	String (filename)
#saveimage	Saves the VFB RGB color channel as an image	String (filename)
#saveallimage	Saves all VFB render channels to separate images or a single vrimg file	String (filename)
#savemultiimage	Saves a multichannel .exr or .vrimg file with all VFB render channels inside	String (filename)	vfbcontrol #savemultiimage "D:\output\image.exr"
#setregion	Sets the render region in pixels, or resets to entire image	Integers: left top right bottom "reset"	vfbControl #setregion 0 0 640 480 vfbControl #setregion "reset"
#getregion	Returns the current left, top, right, and bottom settings for region rendering	None	vfbControl #getregion
#clearimage	Clears the VFB image	None
#duplicate	Duplicates the VFB	None
#hide	Hides the VFB	None
#getchannel	Returns the index of the currently selected render element channel.	None
#getchannelnames	Returns a list of the channels available in the current image	None
#setchannel	Selects the render element channel with an index	Integer	vfbControl #setchannel 0
#clamp	Enables/disables Force color clamping	Boolean	vfbControl #clamp true
#viewclamp	Enables/disables View clamped colors	Boolean
#info	Enables/disables Show Pixel information	Boolean
#pixelaspect	Enables/disables Use pixel aspect	Boolean
#stereo	Sets the Stereo value using an integer: 0 - Inactive 1 - Red/cyan mode 2 - Green/magenta mode	0 \| 1 \| 2	vfbControl #stereo 1
#pos	Controls the position of the VFB window: <top> - the vertical coordinates of the VFB window <left> - the horizontal coordinates of the VFBwindow "reset" - returns the VFB window to its default position Note: Running without any arguments will return the current position of the VFB window.	Integers: top left "reset"	vfbControl #pos 100 150 vfbControl #pos "reset"

VFB Color Correction Options

Parameter	Description	Arguments	Examples
#showcc	Shows/hides the Color Corrections panel	Boolean
#exposure	Enables/disables Exposure correction	Boolean
#whitebalance	Enables/disables White Balance correction	Boolean
#huesat	Enables/disables Hue / Saturation correction	Boolean
#colorbalance	Enables/disables Color Balance correction	Boolean
#levels	Enables/disables Levels correction	Boolean
#curve	Enables/disables Curve correction	Boolean
#bkgr	Enables/disables Background Image correction	Boolean
#lut	Enables/disables LUT correction	Boolean
#ocio	Enables/disables OCIO correction	Boolean
#icc	Enables/disables ICC correction	Boolean
#srgb	Enables/disables sRGB gamma correction	Boolean
#ccociovt	Sets OCIO View Transform by number in the dropdown list	Integer
#ccocioics	Sets OCIO Input Colorspace by number in the dropdown list	Integer
#ccociodd	Sets OCIO Display Device by number in the dropdown list	Integer
#ocioinputcolorspace	Sets OCIO Input Colorspace by name	String
#ociodisplaydevice	Sets OCIO Display Device by name	String
#ocioviewtransform	Sets OCIO View Transform by name	String
#itemsociocs	Returns a list of all available OCIO Input Colorspace values	None
#itemsociodd	Returns a list of all available OCIO Display Device values	None
#itemsociovt	Returns a list of all available OCIO View Transform values	None
#itemsiccri	Returns a list of all available ICC Rendering Intent values	None
#colorbalancemode	Sets the Color Balance mode with an integer: 0 - All 1 - Shadows 2 - Midtones 3 - Highlights	0 \| 1 \| 2 \| 3	vfbControl #colorbalancemode 3
#colorbalancevalue	Sets the Color Balance values for Cyan, Magenta, Yellow	# # # Where each # is an integer or float	vfbControl #colorbalancevalue 0.2 0 0.1
#huesaturationvalue	Sets the Hue/Saturation values forHue, Saturation, Brightness	# # # Where each # is an integer or float
#cclevels_rgb #cclevels_red #cclevels_green #cclevels_blue	Enables/disables color components in Levels correction	Boolean
#bkgrimgasforegr	Enables/disables the use of Background correction image as foreground	Boolean
#lutconverttolog	Enables/disables Log space conversion before applying LUT	Boolean
#cciccblackpoint	Enables/disables ICC black point compression	Boolean
#cciccrenderintent	1 - Perceptual 2 - Relative colorimetric 3 - Saturation 4 - Absolute colorimetric	1 \| 2 \| 3 \| 4
#setexposure	Sets Exposure value	Float
#sethighlightburn	Sets Highlight Burn value	Float
#setcontrast	Sets Contrast value	Float
#setlevelsmin	Sets Levels min value	Float
#setlevelsmax	Sets Levels max value	Float
#setwhitebalanceval	Sets White Balance Temperature value	Float
#getexposure	Returns the current Exposure float value	None
#gethighlightburn	Returns the current Highlight Burn value	None
#getcontrast	Returns the current Contrast float value	None
#getlevelsmin	Returns the current Levels min float value	None
#getlevelsmax	Returns the current Levels max float value	None
#getwhitebalanceval	Returns the current White Balance Temperature float value	None
#loadbkgrimage	Specifies file for Background image correction	String (filename)
#loadlut	Specifies file for LUT correction	String (filename)
#loadocio	Specifies file for OCIO correction	String (filename)
#loadicc	Specifies file for ICC correction	String (filename)
#loadcurve	Load Curve shape from the specified .bcurve file	String (filename)
#savecurve	Save Curve shape in the specified .bcurve file	String (filename)
#saveglobalccpreset	Save Global preset for the Corrections control panel to a specified .vccglb file	String (filename)
#loadglobalccpreset	Load Global preset for the Corrections control panel from a specified .vccglb file	String (filename)
#saveccpreset	Save preset for corrections control rollout to a specified file. Presets for each separate Correction control rollout use different file extensions.	String (filename)
#loadccpreset	Load preset in corrections control rollout from a specified file. Presets for each separate Correction control rollout use different file extensions.	String (filename)
#resetcc #resetccexp #resetccwb #resetcchsl #resetccbal #resetcclvl #resetcccrv #resetcclut #resetccicc #resetccocio #resetccbgimg	Resets parameters from corresponding Correction Control rollouts to default values.	None	vfbcontrol #resetcc - Resets all correction control parameters vfbcontrol #resetccbal - Resets only parameters in Color Balance rollout
#bkgrimgfile #lutfile #iccfile #ociofile	Returns the filename (string) used in the corresponding Correction Control rollout	None

VFB History

Parameter	Description	Arguments	Examples
#showhistory	Shows/Hides History panel	Boolean
#historytemppath	Returns the path used for History Directory	None
#historymaxsize	Size of VFB History in MB	Integer
#historyselect	Selects a History image based on index. Selection is used in conjunction with the commands that follow. First image has 0 index.	Integer	vfbControl #historyselect 2
#historyload #historysave #historyseta #historysetb #historyremove	Performs an operation on the History image that was selected with #historyselect on the previous line	None	vfbControl #historyselect 0 (required before next command) vfbControl #historyseta
#historyclear	Deletes all images from history	None
#historycomment	Adds a comment to the History image that was selected with #historyselect on the previous line	String	vfbControl #historyselect 1 vfbControl #historycomment "Rendered with GI off"

Lens Effects

Parameter	Description	Arguments	Examples
#bloom	Turns on/off Bloom	Boolean	vfbControl #bloom true
#glare	Turns on/off Glare	Boolean
#bloomfill	Turns on/off Bloom Fill Edges	Boolean
#glarefill	Turns on/off Glare Fill Edges	Boolean
#bloommode	Sets the Bloom mode	"image" \| "both" \| "renderelem"	vfbControl #bloommode "image"
#glaremode	Sets the Glare mode	"image" \| "both" \| "renderelem"
#glaretype	Sets the Glare type	"image" \| "rendercam" \| "camparams"
#bloomweight	Sets Bloom Weight value	Float
#bloomsize	Sets Bloom Size value	Float
#bloomshape	Sets Bloom Shape value	Float
#glareweight	Sets Glare Weight value	Float
#glaresize	Sets Glare Size value	Float
#bloomintensity	Enables/disables Bloom Mask by Intensity	Boolean
#bloomobject	Enables/disables Bloom Mask by Object ID	Boolean
#bloommaterial	Enables/disables Bloom Mask by Material ID	Boolean
#glareintensity	Enables/disables Glare Mask by Intensity	Boolean
#glareobject	Enables/disables Glare Mask by Object ID	Boolean
#glarematerial	Enables/disables Glare Mask by Material ID	Boolean
#bloomsetintensity	Sets Bloom Intensity mask value	Float
#glaresetintensity	Sets Glare Intensity mask value	Float
#bloomgetintensity	Returns Bloom Intensity mask float value	None
#glaregetintensity	Returns Glare Intensity mask float value	None
#bloomsetobject	Sets Bloom Object ID mask value	Integer
#bloomsetmaterial	Sets Bloom Material ID value	Integer
#glaresetobject	Sets Glare Object ID mask value	Integer
#glaresetmaterial	Sets Glare Material ID value	Integer
#bloomgetobject	Returns Bloom Object ID mask integer value	None
#bloomgetmaterial	Returns Bloom Material ID integer value	None
#glaregetobject	Returns Glare Object ID mask integer value	None
#glaregetmaterial	Returns Glare Material ID integer value	None
#glarediffraction	Enables/disables Glare Difraction	Boolean
#glareuseobstacle	Enables/disables Use Obstacle image	Boolean
#glareblades	Enables/disables Blades	Boolean
#glaresetblades	Sets Glare Blades number	Float
#glarebladesrot	Sets Glare Blades rotation	Float
#glarefnumber	Sets Glare F-Number value	Float
#glaregetblades	Returns Glare Blades number float value	None
#glareimage	Specifies Glare Image	String (filename)
#glareobstacleimage	Specifies Glare Obstacle image	String (filename)

Stamps

Parameter	Description	Value Options	Examples
#stamp	Enables/disables the stamp	Boolean	vfbControl #stamp true
#stamphalign	Sets horizontal alignment for stamp	"left" \| "center" \| "right"
#stampvalign	Sets vertical alignment for stamp	"top" \| "bottom"
#stamptext	Sets the text string to appear on the stamp	String	vfbControl #stamptext "Test rendering"

Debug Shading

Parameter	Description	Value Options	Examples
#debugshading	Enables/Disables Debug Shading	Boolean	vfbControl #debugshading true
#debugshadinglockedselection	Switches from Isolate Selected to Isolate Locked Selection Debug Shading mode	Boolean	vfbControl #debugshadinglockedselection true
#debugshadingmode	Sets Debug Shading mode with an integer: 0 - Isolate Selected/Isolate Locked Selection; 1 - Lighting; 2 - Ambient Occlusion; 3 - Wireframe; 4 - Normals; 5 - UVs; 6 - Barycentric coordinates	Integer	vfbControl #debugshadingmode 1
. ipr_debugshading_wireframe_subtris	Shows/Hides subtriangles in Wireframe shading mode.	Boolean	renderers.current.ipr_debugshading_wireframe_subtris true
.ipr_debugshading_wireframe_width_pix	Sets pixel width for Wireframe shading mode.	Float	renderers.current.ipr_debugshading_wireframe_width_pix 0.5
.ipr_debugshading_ao_radius_pix	Sets radius in pixels for the Ambient Occlusion shading mode.	Float	renderers.current.ipr_debugshading_ao_radius_pix 20

Environment Variables

Some aspects of the VFB can also be controlled with various environment variables:

Variable Name	Description
VRAY_VFB_SRGB	Turn On (1) or Off (2) sRGB option of V-Ray VFB by default.
VRAY_VFB_PIXEL_ASPECT	Turn On (1) or Off (2) Use pixel aspect option of V-Ray VFB by default.
VRAY_VFB_GLOBAL_PRESET_FILE_USE	Enable (1) or Disable (0) automatic loading of a global .vccglb preset for the VFB.
VRAY_VFB_GLOBAL_PRESET_FILE	Specify default .vccglb filename (string) to be used when loading automatic global preset.
VRAY_VFB_ICC	Enable (1) or Disable (2) the ICC correction in VFB by default.
VRAY_VFB_ICC_FILE	Specify default ICC correction file for V-Ray VFB. It will be automatically loaded when ICC is enabled.
VRAY_VFB_OCIO	Enable (1) or Disable (2) the OCIO correction in V-Ray VFB by default.
VRAY_VFB_OCIO_INPUT_COLORSPACE	Specify default input OCIO color space. A default OCIO configuration can be specified by the OCIO environment variable.
VRAY_VFB_OCIO_DISPLAY_DEVICE	Specify default OCIO display device. A default OCIO configuration can be specified by the OCIO environment variable.
VRAY_VFB_OCIO_VIEW_TRANSFORM	Specify default OCIO view transform. A default OCIO configuration can be specified by the OCIO environment variable.
VRAY_VFB_LUT	Enable (1) or Disable (2) the LUT correction in V-Ray VFB by default.
VRAY_VFB_LUT_FILE	Specify default LUT correction file for V-Ray VFB. It will be automatically loaded when LUT is enabled.
VRAY_VFB_AFFECT_SWATCHES	Apply VFB corrections to swatches in the Material Editor: 0 - none 1 - OCIO only 2 - all corrections except sRGB 3 - all corrections including sRGB
VRAY_VFB_ALWAYS_ON_TOP	Specify a ALWAYS ON TOP behavior: 0 - disabled 1 - force enable always on top 2 - force disable always on top