1. Can houdini.env live anywhere else but in $HOME? Jeff W. suggests that you can put it anywhere in this post:

https://www.sidefx.com/forum/topic/13416/#post-63585 [sidefx.com]

But it seems as though the only one Houdini reads is the one in $HOME. Even if it can't find one in $HOME it will make a template one.

2. Can you change HOUDINI_PATH or OTL_SCAN_PATH in 456.cmd after you've double-clicked a .hip file and expect that any new OTLs/HDAs that you add to either path in 456.cmd will be scanned automatically in that session? Or is it too late at that point i.e. those particular env vars need to be set prior to launching?

I am trying to find a mechanism for when a user double clicks a .hip file in a given $JOB such that the specific versions of Arnold and Redshift are loaded associated with that $JOB. Simplest method I can see is if there is a houdini.env sitting in each $JOB (as Jeff suggests) but this doesn't seem to work.