When using the hdaprocessor in tops how do you get Unreal to recognize a global variable. Is there a certain var name you should use like in Unity with the HEU_ENVPATH. I know in Unity you can create a env file that is then rocognized in Houdini. What is the process for Unreal in order to be able to use the hdaprocessor node in Unreal so I can point it to the correct directory of the hdas?

If you mean the houdini.env file, that should also work with the UE4 plugin. For example you can define a PROJ_HDAS var in your houdini.env and use it in the hdaprocessor parm as $PROJ_HDAS/asset.hda

That’s what I was wondering and the env/json file should be in your user_prefs_dir or in the case of json files the user_prefs_dir/packages? Or should it be in the unreal project folder?

It's the former. The same startup files as interactive houdini are used.

You can also specify a custom .env file for use with the UE4 plugin in the plugins settings.
(Under Houdini Engine Initialization, Houdini Environment files)

For the PDG Asset Link, you can set the “Working Directory” param on the scheduler, and use $PDG_DIR on the HDA Processors.
The Working Directory can then be exposed on the HDA, and set directly in Unreal.

Thanks for the help