Damien Pernuit


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Failed to locate or load libHAPIL.dll June 12, 2018, 3:48 p.m.

Yes, that's it!

For HDAs you should set the parameters using the type properties.

Also remember to use relative paths when referencing something in HDAs, as your hda's node might have different names when created via HEngine (or you can have the same hda multiple times).

Failed to locate or load libHAPIL.dll June 12, 2018, 9:47 a.m.


Could you send us the content of your output log when trying to instantiate an hda?

Can you also try using one of the default Houdini Tools shipped with the plugin, like the rock generator for example.
(they are in Place Mode > Houdini Engine)

The fact that no error pops up and that the “default” parameters (transform + subnet) show up seems to indicate that HEngine is running correctly. Those parameters wouldn't be here if HE wasnt initialized properly.

I had a look at your building hda, and there's a few thing that explains why its not creating geo:
- The object merge in the output geo is using an hardcoded absolute reference, you should always use relative ref in hdas…
- Because of that absolute ref, the path in it is incorrect, and since Building doesnt have a display flag, it's never cooked.
- Inside the Building geo, a baselength parameter is referenced, but that parameter doesnt exist, so Building cant cook..

To debug this type of issue, you can always open the internal houdini scene in unreal:
(ctrl + alt + o, or file > open scene in houdini )
This should be really helpful for troubleshooting these kind of issues.

Failed to locate or load libHAPIL.dll June 4, 2018, 10:43 a.m.


The houdini logo and placed hdas not cooking are the side effects of the plug-in being unable to find the Houdini Engine dlls.
Not sure exactly what happened, especially if you have not updated houdini or UE4.

In process sessions have been removed a few months ago, as UE4.19 had library conflicts with HAPI that conflicted with Houdini Engine in process sessions. Pipes and sockets should now be used. (internally, the plugin will default to pipe if you had in session before)

Here's a few things you can try to fix that:

- If you've copied the plugin manually, make sure you only have it once in Unreal.
The plugin should be in Plugins/Runtime/HoudiniEngine.

- In projects settings / Houdini Engine
set the session to either pipe or socket, and make sure the start automatic server checkbox is ticked. Restart unreal, or in the Cmd line, type Houdini.RestartSession.

- If you still get the same issue, then tick “Use Custom Houdini Location” and set the path under it to your houdini bin directory. In your case, it should be:
C:\Program Files\Side Effects Software\Houdini 16.5.473\bin
Then either restart unreal, or type Houdini.RestartSession in Unreal's Cmd line.

Please let me know if this solved your issue.