V-Ray for Maya Environment Variables
Textures and render assets
There are some environment variables that affect the operation of V-Ray. Some of these variables are in effect in both V-Ray Standalone and V-Ray for Maya, while some of them are pertinent to V-Ray Standalone only. The variables that are valid for V-Ray Standalone only are marked with (standalone).
VRAY_AUTH_CLIENT_FILE_PATH - path to the file vrlclient.xml file containing information about the license (e.g. license server IP address and port).
VRAY_CONNECT_TIMEOUT - the timeout (in milliseconds) when connecting to the license server.
VRAY_CMD_PREFIX (standalone) - specifies command-line options for V-Ray standalone which are prepended to the actual command line.
VRAY_CMD_SUFFIX (standalone) - specifies command line options that are appended to the actual command line.
VRAY_ASSETS_PATH - this variable specifies a list of paths where V-Ray will look for textures, GI cache files etc. Initially, V-Ray will attempt to look for an asset in the path specified in the scene. If this fails, V-Ray will go through the paths in the VRAY_ASSETS_PATH variable and try to find a file with the same name. On Windows, paths are separated with semicolon ';' and on Linux and Mac OS X - either a colon ':' or semicolon ';'
VRAY_TEXTURES_LOAD_16BIT_AS_8BIT - if set to 1, V-Ray will load 16-bit PNG and TIFF texture files as 8-bit in memory.
VRAY_PLUGINS_x86 and VRAY_PLUGINS_x64 (standalone) - specifies a list of paths for additional V-Ray plugins. Paths are separated with ';' on Windows and ';' or ':' on Linux/Mac OS X.
VRAY_TEXTURE_CACHE - specifies the size, in megabytes, of a separate texture cache to be used for tiled OpenEXR files. If this is not present, or the value is 0, the same same cache is shared between dynamic geometry and tiled textures. One of the advantages of a separate texture cache is that it is persistent across the frames when rendering an animation.
VRAY_VFB_SRGB (standalone) - if set to 1, the sRGB button of the V-Ray VFB is automatically switched on when V-Ray Standalone starts.
VRAY_VFB_LUT (standalone) - if set to 1, the LUT color correction is enabled by default. The LUT file is specified with the VRAY_VFB_LUT_FILE environment variable.
VRAY_VFB_LUT_FILE - specifies the path and name of the LUT file.
VRAY_VFB_PIXEL_ASPECT (standalone) - if set to 1, the pixel aspect correction for the VFB is automatically enabled.
VRAY_DR_CONTROLPORT - specifies the port number used for distributed rendering.
VRAY_DR_SUBNET - specifies the subnet mask for broadcast messages. This currently used only when a render server is started, so that it can join a DR render.
VRAY_USE_NORMAL_DIFFERENTIALS - if this is set to 1, V-Ray will use the surface curvature when calculating ray differentials for secondary rays for reflection, refraction and GI. This is typically useful with tiled OpenEXR textures, as it will produce a more accurate estimate for the required MIP map level (which otherwise might be overestimated resulting in a more detailed level being loaded than is really necessary).
VRAY_OPENCL_DEVICES (standalone) - a comma-separated list of the devices to use for OpenCL rendering with V-Ray RT. Each device is identified by a zero-based index; the V-Ray RT render server will normally print a list of all available OpenCL devices together with their indices.