Jeff Lim

Finally got it to work, but not on SteamOS XD
It worked thru proton, the compatibility layer.

Here are the steps (from what I can recall):

Optional Pre-Req

1. Go to desktop mode in steam deck.
   
2. Go to Discover
   
3. Download and install ProtonUp-Qt
   
4. Run the program, and grab the latest proton (I was able to test it on GE-Proton8-1)
   

Installing Houdini

1. Go to desktop mode in steam deck.
   
2. Download the windows version of Houdini.
   
3. Load up the Steam app (still in desktop mode)
   
4. Add a non-steam game
   
5. Locate your Houdini installer
   
6. After adding it to your library, set its compatibility mode, and select the proton version you prefer.
   It's possible that just the default proton versions that comes with the Steam Deck could probably work (I haven't tried)
   
7. Start the installer
   
8. After the install, you may remove the non-steam app from your library.
   

Starting Houdini

1. On the Steam app, add another non-steam game
   
2. Locate the Houdini executable - It's usually found in:
   /home/deck/.local/share/Steam/steamapps/compatdata/(random_number)/pfx/drive_c/Program Files/Side Effects Software/Houdini XX.X.XXX/bin/houdini.exe
   You may also need to show all files.
   The random number can be different in your case, just look for the correct one using the timestamp.
   
3. After adding the Houdini.exe, when i tried launching it, i had licensing errors.
   For now, what worked was to use the sidefx.com server.
   
4. To also make launching it smoother, i also added hkey.exe as a non-steam game.
   I start this first before starting Houdini.
   hkey is also found in the bin folder.
   

Some Notes on usage:

• You may notice that the touchpad might sometimes stop working when starting up Houdini (or other non-steam games).
  Simply press the Steam button, and it should be back.
  
• Get familiarized the Steam Deck default button shorcuts to navigate within the different contexts in Houdidi
  This site has a list: https://stealthoptional.com/gaming/steam-deck-shortcuts/ [stealthoptional.com]
  Or if you are in Game-mode, you can press and hold the Steam button to view the shortcuts (and memorize them!)
  
• I also found it difficult to type, so i tend to use D-Pad to individually select keys in the floating keyboard.
  
• SideFX support also noted that from what they heard, performance is not that great. So thread lightly.
  So far i've only really started playing around simple note setups~ I might update this thread if i discover new tidbits worth sharing.
  
• If you don't have keyboard/mouse connected to Steam Deck, you can try installing Steam Link on your desktop, then remotely control Steam Deck in desktop mode.
  
• This was a fun troubleshooting exercise
  

Confirmed:

Use this command before installing Houdini:
sudo steamos-readonly disable
I now am able to run hkey without the errors.
And it is now able to use my local machine as the server, with a proper server code.

But...

I'm back again with the Segmentation Fault issue.

Also, i'll also need to monitor if this indeed will retain after an OS update.

For now, i'll dig more on the Segmentation thingy~

Got a reply from Support.
Unfortunately, since SteamOS is not a supported OS, they are unable to support it directly.
But they know some people were able to make it work.

So i did further digging.
It turns out I was not completely reading the installation output logs. XD
It has a warning saying that some install error have occured.
I didn't notice the error because the output logs i saw were mostly the SideFX Labs stuff getting installed.
After reinstalling without the Labs stuff, I now saw the issue:

The installer was unable to install some files due to having some directories as Read-only file system.
In particular:
/usr/lib/sesi
when i tried manually creating the directory using:
sudo mkdir /usr/lib/sesi
it still told me the same Read-only file system error.

a page i found here [www.reddit.com] says i could use this command:
sudo steamos-readonly disable
But warns also that some root files could be wiped if the OS is updated.

So I'm wondering if anyone knows if it's possible to install the License Management Tools onto a different directory.
Preferably to local folder, so that it won't likely to get wiped.