Page History
...
Environment Variables
...
You can include environment variables in the form ${VAR_NAME} which are replaced with the value of the respective environment variable during rendering. For example, if the file name is specified as${TEX_PATH}/${PROJ_FOLDER}/mytexture.exr, then V-Ray will look up the environment variables TEX_PATH and PROJ_FOLDER and replace the tags with their values. Suppose that TEX_PATH is set to c:/textures and PROJ_FOLDER is set to proj1, then the final bitmap file name will be expanded as c:/textures/proj1/mytexture.exr
...
You can specify user tags between < and > brackets. At render time, V-Ray takes the tag name and looks it up in the V-Ray User Attributes list for the shaded object to determine the value of the tag. This allows a single File node to use different file textures on different scene nodes. For example, you could specify the file name in the File node as /path/to/texture/<objtag>_diffuse.png and then for the objects that use the material, add a V-Ray User Attributes string with values like objtag=head or objtag=body etc. Then during rendering, V-Ray will attempt to load and use the texture file /path/to/texture/head_diffuse.png for the first object and/path/to/texture/body_diffuse.png on the second.
Starting with V-Ray 5.0, when user attributes are used at the beginning of a file path, V-Ray treats the path as absolute. To mimic the old behavior, use the fake user attribute <PROJECT_PATH> that forces the path to be interpreted as relative. For example, if you have an old scene with an Image name = <filename>.jpg where 'filename' is not a full absolute path but just the jpg name, you can add the fake attribute in front: Image name = <PROJECT_PATH>/<filename>.jpg and it will be loaded correctly.