Greetings,

We're using Houdini 17.352 plugin for Unreal 4.20. The idea is that, since our project is self contain on Perforce, we add and compile the plugin from git hub (17 branch). The twist is that the plugin is added to the project instead of the engine folder. This procedure seems to be troublesome as dragging any Houdini asset in the Unreal viewport is spitting out an error where the hapi.dll mismatch.

Is this an known issue?

Note: We're adding the plugin to the project's folder in the hope to avoid installing the whole Houdini package on our build machines.

Hi,

The plugin should work just fine from the project folder.
The version mismatch you're getting probably comes from the github source being built with a more recent version of Houdini, and specifically, with a more recent version of the Houdini Engine API.

Instead of using the github source, you can also use the source of the plugin in your houdini install folder (in the engine/unreal/4.20 folder)
You can ignore the Binaries and Intermediate folders if you're planning on building the plugin.

Thank you for you're suggestion,

While the plugin is nested within the project's folder, should the plugin be removed from the Unreal Engine's folder?

Hi,

That's correct, if you want to have the Houdini Engine plugin in the project setting, then you should make sure it's not also in the engine's plugin folder at the same time.

Might sound a bit silly but is there an official way to uninstall the UE4 plugin only?

In H17.0, you could use the Houdini Engine Plugin Installer shelf tool (in the houdini engine shelf).
It should automatically detect the Engine plugin, and offer you to uninstall it.

Or you could simply delete the “Plugin/Runtime/Houdini Engine” folder.

Very well,

Everything seems to work nicely until we drag an Houdini asset into an Unreal level:

Houdini Installation was not detected.Failed to locate or load libHAPIL.dll. No cooking / instantiation will take place.

Any idea?

Hi,

This means that the plugin failed to automatically detect the Houdini install folder.
You can set a path manually by going to project settings > Houdini Engine > Custom folder, enable it then point it to your houdini bin folder (“Houdini 17.0.XXX/bin”), then either restart unreal, or use the Houdini.restartSession command.

If the plugin complains about a version mismatch after that, then you should either use the plugin sources from the installed version of Houdini, or install a more recent daily build.

Awesome,

Copying the plugin from the engine to the project reveals that some files are missing when packaging the project for Windows:

Plugins\Runtime\HoudiniEngine\Source\HoudiniEngineRuntime\Public\HAPI\HAPI.h
Plugins\Runtime\HoudiniEngine\Source\HoudiniEngineRuntime\Public\HAPI\HAPI_API.h
Plugins\Runtime\HoudiniEngine\Source\HoudiniEngineRuntime\Public\HAPI\HAPI_Common.h
Plugins\Runtime\HoudiniEngine\Source\HoudiniEngineRuntime\Public\HAPI\HAPI_Helpers.h

I basically took the one from GitHub and put them in the HAPI folder. A bit frankensteinish but it worked!

Thank you for your support, much appreciated.

Yeah, manual copy should work, but actually those “missing” files are normally found/included in the houdini install folder, in “Houdini 17.0.XXX\toolkit\include\HAPI”.

But since the Plugin fails to detect your Houdini install, it is instead looking for them in “Source\HoudiniEngineRuntime\Public\”.

I copy from engin to my project plugin, it works well.
But…the icon is missing.

Hi,
I fixed the missing icons when the plugin is in the project folder recently.