Session Sync Example?

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Can anyone point me to a video or documentation about how session sync can be used? I've been looking at the v2 alpha, and I'm confused about how session sync is to be used. I can get it “working” in that houdini opens with the GlobalNodes subnet and session interface panel, but my expectation was to somehow see my HDAs as well ( similar to when i just use the open scene in houdini option). What can i expect to see changed when this is functioning? Is it simply a link between the top level hda parameters and inputs? Thanks, great work on the alpha!
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Hi,

When opening session sync, we need to restart the houdini session, so your HDA will only show up if you modify them, or recook/rebuild them.

When using Session sync, you can make change to your HDA in Houdini, and they will be picked up automatically by Unreal.
So you can change parameters in your HDA in H for example, or even unlock the HDA, and start doing anything in H…

you can literally use an HDA wrapping an object merge node, point the path to a node you've manually created in Houdini, and see whatever you're creating in H appear in Unreal…

Version 2 doesnt have docs for now, aside from the git hub repo's wiki which has a few helpful info, but as far as SessionSync is concerned, you can have a look at the unity plugin's doc on Session Sync, but it is also fairly minimal:

https://www.sidefx.com/docs/unity/_session_sync.html [www.sidefx.com]

Aside from NodeSync which is only available in Unity, both plugin will behave similarly.
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Hi,

I am new to Houdini in general but very experienced on the UE4 side and have been trying the Alpha 3.2 plugin, however it looks like Session Sync does not correctly support the Steam version of Houdini Indie, which is what I have installed.

Selecting Open Houdini Session Sync results in the editor freezing with the following in the logs in Visual Studio:

[2020.08.19-02.57.35:516][609]LogHoudiniEngineEditor: Opening Houdini Session Sync.
[2020.08.19-02.57.35:516][609]LogWindows: Warning: CreateProc failed: The system cannot find the file specified. (0x00000002)
[2020.08.19-02.57.35:516][609]LogWindows: Warning: URL: E:/SteamLibrary/steamapps/common/Houdini Indie/bin//houdini -hess=pipe:hapi
'UE4Editor.exe' (Win32): Loaded 'E:\SteamLibrary\steamapps\common\Houdini Indie\bin\libHARC.dll'. 
'UE4Editor.exe' (Win32): Unloaded 'E:\SteamLibrary\steamapps\common\Houdini Indie\bin\libHARC.dll'
'UE4Editor.exe' (Win32): Loaded 'E:\SteamLibrary\steamapps\common\Houdini Indie\bin\libHARC.dll'. 
Exception thrown at 0x00007FFACF8AA719 in UE4Editor.exe: Microsoft C++ exception: apache::thrift::transport::TTransportException at memory location 0x000000DBCE179200.

It doesn't seem to be looking for the correct executable:

Warning: URL: E:/SteamLibrary/steamapps/common/Houdini Indie/bin//houdini -hess=pipe:hapi

There is no houdini.exe in the Steam install. It seems to be hindie.steam.exe.
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Hi Jerome,

Thanks for reporting this one!
Yes, that's a bug on the v2 side, we should indeed look for the steam exes as well when starting session sync!
(and I suppose that other actions like “open in Houdini” likely have the same issue).

Alternatively, you can manually start Houdini Indie from steam, start session sync directly in Houdini (via Windows > Houdini Session Sync), then in unreal, manually restart the session (Houdini Engine > Restart Session).
You'll just need to make sure that the session sync settings match the session settings that you have selected in the plugin's setting in Unreal.
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I ended up just changing the plugin code to look for the Steam exe which did fix the launching issue (I didnt have time to try session sync yet), but I think there are other somewhat fundamental problems with the Steam install coming from how Steam works in general.

For example, Steam will always ask for confirmation before launching an .exe with an argument (it shows you what the argument is). Not only is this annoying, but the popup does not even appear on top of UE4 and does not focus Steam so you need to manually look for it (you have no idea a popup is waiting for input).

If Steam Houdini is already running, any of the options that normally open Houdini won't do anything. I'm not sure if that's because the plugin currently doesn't look for existing Houdini processes, or if its because it's trying to run a second instance of the app, which Steam does not allow.

In any case, I've requested a refund for my Steam version so that I can use the standalone version and keep testing this plugin… I did not understand that my license would be 100% tied to the Steam install when I purchased on Steam (I did so for the extra convenience). I've already talked to SideFX support about this and there's nothing they can do unfortunately.
Edited by JeromeParent - 2020年8月20日 15:30:58
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I started Session Sync from Houdini and Restarted my session in Unreal as instructed, and everything says its successfully connected but I still am not seeing any indication of Session Sync working.

I created a simple Box HDA which I imported into Unreal, but any changes made to the HDA in Houdini afterwards (and I made sure to save the asset in Houdini) were not reflected in Unreal unless I clicked Rebuild Asset. From what I can see on the Unity Session Sync documentation, this should have worked, no?
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