When I use File >> New Project, the field "Project Path" defaults to $home/Houdini Projects. I would like to change this WITHOUT changing my $home variable as this might impact on other software. How do I do that?

Not sure if this helps but here is how I setup projects...

I've already added D:/Art/Projects as a shortcut to the file browser using the "+" icon in the bottom left of file browser.

1. File>New Project
2. Type Project_Name
3. Use file browser icon, Select D:/Art/Projects
4. File>Save As
5. Click $JOB, Type in PN_v1.hiplc

Folder structure looks like this D:/Art/Projects/Project_Name/PN_v1.hiplc
Once this structure is setup, I use $HIP for file references (instead of $JOB) to avoid potential issues in the future.

I must say I have been surprised that after clicking file->set project
to an existing folder, $HIP is not set to what I expect.

I will often open Hscript Textport
and type
echo $HIP

just to confirm that $HIP is set to the correct folder.

Something is amiss.

As far as I'm aware, Set Project is used for $JOB. $HIP is the current location of the Houdini file so Set Project won't (and shouldn't) change $HIP. Unless I'm misunderstanding something?

robsdesign
As far as I'm aware, Set Project is used for $JOB. $HIP is the current location of the Houdini file so Set Project won't (and shouldn't) change $HIP. Unless I'm misunderstanding something?

This is correct. $HIP is unrelated to the project itself.

In terms of solving OPs problem, I don't know how to change the path that exists in that specific field. However, if you add/modify a jump.pref folder in the My Documents\houdiniXX.X directory, you can add custom paths to "favorites" you can jump to in the file browser, including environment variables. In combination with creating a custom package file (https://www.sidefx.com/docs/houdini/ref/plugins.html) where you define your own environment variables, this could be a viable solution.