I'm trying to understand the different ways I can get geometry from Unreal into my HDA.
Creating a bunch of HDA input slots works fine, however I find myself changing and reordering them a lot and that leads to issues of having to update my code.
If I'm understanding the docs, I can use the operator path approach and create Object Merge nodes which are exposed as parameters in the HDA, rather than Inputs.
However, if I do this, I see only a single text entry field appear in UE4 rather than a geometry selector that comes with the Input method. I'm pretty sure that means I did something wrong.
Either I'm using a too-old version (Houdini 5.5, UE4.14), or I'm missing some critical step, or I've misunderstood the documentation.
Can someone provide a missing step?

As an add-on, I would love to see some HDA/UE4 examples to learn from but haven't found any. If there's a repo that I haven't found showing examples of how to achieve this I would be happy to peruse.
Thanks!

-Len

Hi,

To get those object path inputs, all you have to do is to create an object merge node, and simply expose its “object1” (objpath1) parameter on the HDA.
When instantiated in Unreal, the HDA should have the object path input available as a regular SOP input (with the input type selector etc..)

This certainly work for current/recent versions of the plugin, and also should on the 15.5 / 4.14 plug-in, but I cant tell for sure with such an old version of the plugin.

Thanks. It must be a fixed older bug then, since I've exposed objpath1 by dragging the obj merge param into the HDA parameters.
I do indeed get a corresponding input on the Unreal side, just a single blank text field in the “Houdini Parameters” section with no other display.
Oh well…I should be able to upgrade one of these days and that should solve it.

EDIT: Was able to test my HDA with a newer version (16.5) and I now see the correct interface inside Unreal (4.18). It seems it was indeed a matter of updating and getting the fixes to the engine plugin.