Is it only me or do others see this as well? If I remember, Houdini startup was fast a while ago, but lately, it takes a while to boot up. Do you have any ideas about what's up with that? It's not a big deal, but I was just wondering.

If you have many HDAs that get loaded from server, it will add allot of startup time.

If you are loading Redshift from the server it will also add allot of time, Redshift affect Husk startup time allot.

SideFX has it logged as a bug (packages making load times longer). It's a Windows thing. On Linux Houdini boots up in 5 seconds max. But you're right, everybody sees it, and with H20.5 it's gotten visibly slower.

Makes more sense now, as I was on Linux until this Wayland transition that forced me back to Windows for now, and I know that it usually has a really fast boot.

I think you can switch between X11 and Wayland easily, at least on Gnome. I've switched back to X11 personally. I'm saying it just in case

Unfortunately, nobara (basically Fedora) doesn't come with x11 at all anymore, and I could install it later in version 40 but now can't even install it some repo problems or something. So for now waiting for Houdini 21 and hope it will support wayland

Interesting to hear Linux has fast startup. At our studio we have to wait up to 2 min using Windows 10

Damn and I thought our studio's 1 minute was bad. RIP

Linux has a faster everything. Mplay pops up faster too, Husk is quicker to start. Someone once told me Windows' slow Houdini startup is related to some sort of internal virus scanning thing, that if you disable all defenses it boots up fast. Not sure if I'm willing to test it

It's ridiculously slow. Even with the Windows Defender off. I don't think there is another DCC that takes so much time to launch (not even Maya).

It's so slow that every time I launch Houdini I launch 3 blank instances just in case that when it crashes I can use another one immediately.

I wish I'm joking.

You can get an idea of where the time is going by running: houdini -profile-startup=/tmp/startup.hperf
You can then load that file into the Performance Monitor for analysis.

If you have labs installed, that's been known to slow down startup, especially if it's loading off a network share.

I`m on Windows 10, I have Labs and plenty of other plugins and packages installed. my startup time is exactly 30s.
But it's all local. I guess this is the main differentiator. I worked on a project last year for a studio were it took 4min to launch.

Well, I just did the test again. I managed to bring back X11 but that is not the point.
On Linux, it was a 10-second lunch, on Windows - 25 sec. Loading the same things from the same location.

I would like to offer you this information that can reduce the loading time (70s to 17s on Windows) of Houdini 20.5 :
1) SideFX Labs must be load in a single HDA.
2) Add Process = houdini.exe to Exclusions in windows anti-virus
(Note (Virus & threat protection settings -> Exclusions) recommends writing the process name with the full path)


source : https://ikatnek.blogspot.com/2025/01/houdini-startup-time.html [ikatnek.blogspot.com]


//* How to make this :*//

1) SideFX Labs load in a single HDA
If you download SideFX Labs from GitHub as a zip file and simply load the directory that was extracted, Houdini's startup time will drop significantly (by more than a minute).

Therefore, you need to bundle the various OTLs into a single file. To do this, use

$ hotl -m SideFXLabs-Development/otls/*.hda test.hda
(test.hda is the target file name) and load only this single HDA.

This will reduce startup time.

!!! Important : If you installed SideFX Labs from the old installer or Launcher, this step is not necessary because the related HDAs are already bundled into a single HDA.


2) Windows Virus & threat protection : Exclusion of the Houdini Process
Virus checkers have a large impact on Houdini's startup time. For example, I use the standard Windows Virus & threat protection for Windows 11, and

if I start Houdini 20.5.457 (including SideFX Labs single HDA) immediately after rebooting the system (OS), it takes 70 seconds.

However, if I add Process = houdini.exe to Exclusions and start Houdini after rebooting the OS in the same way, the time goes down to 17.6 seconds (see the top image), which is about 1/4.

Note that the official website (Virus & threat protection settings -> Exclusions) recommends writing the process name with the full path.


3) The following rule settings were not very effective.

Added Folder = "C:\Program Files\Side Effects Software" (reduced by about 2 seconds)

Added "otl", "hda", and "shelf" to File Type (increased and decreased)

//* End *//

How do you combine the labs hdas in a single file?

@coccarolla According to that post, you need to use the hotl utility [www.sidefx.com]. You should be able to find it in your houdini install folder in bin/ ($HFS/bin). I haven't used it before, but it seems straightforward.

This is the line you need to recreate in your terminal (I assume you're on Windows, you can use Command Prompt EDIT: this command requires Bash to work. Mingw64 Git Bash is one way to get a Bash terminal on Windows):
hotl -m SideFXLabs-Development/otls/*.hda test.hda

Breakdown:
hotlis the path to your hotl.exe
-mis an instruction to merge hdas
SideFXLabs-Development/otls/*.hdashould be the path to your SideFXLabs package. It uses a wildcard * to target all files that have an .hda extension in the otls/ folder
test.hdawill be the new HDA that hotl produces.

In your case, the command could possibly look like this:
"C:\Program Files\Side Effects Software\Houdini 20.5.445\bin\hotl.exe" -m C:\mycustom_sideFXLabs_package_location/otls/*.hda "C:\Users\John\Desktop\single.hda"

Tried it out of curiosity yesterday but I had all sorts of errors.
Wonder if / \ could be an issue.

It could. But also make sure that if you have any spaces in paths that you encase them in double quotes. But in my case the command didn't work when I added double quotes to the SideFXLabs/*hda part, so perhaps that part needs to already be in a path without spaces to begin with.

Also, if you're trying to use it on something else than SideFXLabs I'm not sure if perhaps that /*.hda needs to be changed to /*.hdalc or /*.hda*.

alexmajewski
It could. But also make sure that if you have any spaces in paths that you encase them in double quotes. But in my case the command didn't work when I added double quotes to the SideFXLabs/*hda part, so perhaps that part needs to already be in a path without spaces to begin with.

Also, if you're trying to use it on something else than SideFXLabs I'm not sure if perhaps that /*.hda needs to be changed to /*.hdalc or /*.hda*.

Thanks! I still get and error for these parameters: ...Documents\houdini20.5\packages\SideFXLabs-20.5.487\otls\*.hda" "...\Documents\houdini20.5\packages\labsSingle.hda"

Error is: Invalid or empty library for merge:...

I've just tested disabling Windows Defender. Excluding houdini.exe had ZERO effect in my case. But excluding an entire folder with my Houdini and all my Houdini packages (Redshift, Labs, etc.) made me go down from 01:30 to 0 0 : 2 3. This is crazy.

@coccarolla can you paste the whole command that you use?

alexmajewski
I've just tested disabling Windows Defender. Excluding houdini.exe had ZERO effect in my case. But excluding an entire folder with my Houdini and all my Houdini packages (Redshift, Labs, etc.) made me go down from 01:30 to 0 0 : 2 3. This is crazy.

@alexmajewski Hi, For information, I would like to point out that it is the Houdini process with its full path that needs to be added to the exclusion rules and not the Houdini.exe file.