I have troubles with houdini indie 15.5 and unity 5.4.0b13. It's the first time I tried to use H Engine since H15.5
I am trying to build a simple wall asset. I think I didn't do anything unusual, I just exposed an operator path parameter as a base shape for my wall tool. But the parameter is greyed out, I can't drop anything on it.
Is there a bug with houdini 15.5 ?

If the operator path parameter's filer is set to SOP it should appear above all parameters in Unity in the asset's Input section. We are working on streamlining this but for the moment, all Op Path parameters with supported input types (SOP and OBJ) will be available as inputs in the Input section and grayed out in the main parameter list.