Under the hood, the V-Ray installation relies on the Houdini 3-rd party plugins package system. Houdini's packages are .json files that specify the location of custom modules. For more information, please refer to the documentation on the SideFX website.

The "vray_for_houdini.json" package that is used to load V-Ray when Houdini is started is placed under "$HFS/packages" (e.g. "C:\Program Files\Side Effects Software\Houdini ##.#.###\packages" for Windows) when running the installer. You may set things up differently depending on your studio pipeline.

By default, when using the installer, the location of V-Ray itself is "C:\Program Files\Chaos Group\V-Ray". Just as with the "vray_for_houdini.json", V-Ray itself can be placed anywhere on disk. As long as the "INSTALL_ROOT" variable in the json file points to a valid location, Houdini should be able to find the required modules to load V-Ray.

{
	"env": [
		{ "INSTALL_ROOT" : "C:/Program Files/Chaos Group/V-Ray/Houdini 19.0.383" },

		{ "VRAY_APPSDK"     : "${INSTALL_ROOT}/appsdk" },
		{ "VRAY_OSL_PATH"   : "${INSTALL_ROOT}/appsdk/bin" },
		{ "VRAY_UI_DS_PATH" : "${INSTALL_ROOT}/ui" },
		{ "VFH_HOME"        : "${INSTALL_ROOT}/vfh_home" },

		{ "PATH" : [
			"${HFS}/bin",
			"${VRAY_APPSDK}/bin",
			"${VFH_HOME}/bin"
		]},

		{ "VFH_DSO_PATH" : {
			"houdini_python == 'python2'": "${VFH_HOME}/dso_py2",
			"houdini_python == 'python3'": "${VFH_HOME}/dso_py3"
		}},

		{ "PYTHONPATH" : [
			{ "method": "append", "houdini_python == 'python2'": "${VRAY_APPSDK}/python27" },
			{ "method": "append", "houdini_python == 'python3'": "${VRAY_APPSDK}/python37" }
		]},

		{ "VFU_PLUGINS" : "${VFH_DSO_PATH}/usd_plugins/hdVRay/plugins" },
		{ "VFH_ASSET_PATH" : "C:/Users/USER/Documents/V-Ray Material Library/assets" },

		{ "HOUDINI_DSO_PATH" : "${VFH_DSO_PATH}" },
		{ "HOUDINI_GALLERY_PATH": [
			{ "method": "append", "value": "${VFH_HOME}/gallery" }
		]}
	],
	"path" : [
		"${VFH_HOME}"
	]
}