Ah, bummer. Just got excited to connect my Midi controller to my MacBook Pro running Houdini 19.5.
No devices available. Sadface.

@dpernuit: Ok, we've made the jump to v2 but now that detail attribute doesn't seem to work any more.

So what is the recommended way going forward for getting multiple convex colliders into Unity? The Split by Group is deprecated, which suggests another avenue might be available?

Managed to get a clean repro file and submitted the bug.
Support says it's fixed in 18.0.588. Haven't tested yet.

I'm seeing a new crash in 18.0.566 that occurs when I'm renaming a node that is an instance of an HDA, usually recently (or just) created.
There's no crash log and it technically just hangs forever.
I haven't found repro conditions yet unfortunately but, interestingly, I've seen this in my Mac Indie 18.0.566 and now, just today, my Windows full license 18.0.566.
They have completely different HDA paths and libraries.
The HDAs aren't particular complex, and yet I can't repro reliably.
Anyone see something similar?

EDIT: Just got the hang on renaming an Attribute Wrangle inside an HDA. There were no other dependencies or references to this node in the network (or any other).
I also notice that during the hang Process Manager says about 15% CPU being burned by houdini, so it's still doing…something.

If you vertex paint on a mesh in Unreal and then use that mesh as an input into the HDA, Houdini can use that vertex paint data to scatter things, or whatever.

Using V1 of the plugin to generate static geometry from a UE input spline with parameters to control the result.
I've noticed that when saving/loading maps that contain these actors, the entire Houdini Inputs section can vanish (and the actor fails to cook) until I rebuild. Usually the input spline is disconnected and needs to be reattached. Often all other param values are reset as well.
Can this be caused by pushing updated versions of the HDA to UE? I make mods (add/edit/remove params) to the HDA on a fairly regular basis to get new behaviors, simply saving over the previous. Is this possibly causing issues with the inputs? Is this a known issue is it possibly fixed in V2?

There is an avenue to accomplish this, but it has to be done in C++ AFAIK.

We're on version 1
Considering the jump to version 2 but “alpha” is a scary word.

FWIW, I've had luck controlling distance field generation on HDA-geo, using the detail attribute:
@unreal_uproperty_GeneratedDistanceFieldResolutionScale = 0 or 1;

I don't think you'll ever get an HDA alone to overwrite the original assets but otherwise that should all be do-able from a single HDA using a multi-parm input, among other techniques. You'll need to make sure the HDA is an object-level one, not SOP, as you need distinct objects generated in UE, not a merged single one.

I'd like to send a notification, like a log message, to Unreal's Output Log window for users of my tools to see.
Is this possible? I've tried python print() from within a Python SOP with no luck.
The main point is when my networks detect issues (no prims, for example) and need to switch to other paths, I'd like the user to know.
I've also tried setting param values (string and label) but there seems to be maybe some caching going on that is keeping these from updating correctly in UE.

Dealing with this issue right now.
Found I can set this Detail attribute to set the property:
@unreal_uproperty_GeneratedDistanceFieldResolutionScale = 1;

Weirdly, won't process this when first placing HDA. Change a param or force recook and it works as intended with Mesh Distance Fields updating.

I know we're several years on, but I'm finding this, or similar bug in Houdini 18.0.499 and Unreal 4.25.
We are heavily using HDAs at our studio that generate geometry that needs to remain non-baked.
I've noticed some uproperties get reset after a map save, then reload. Specifically unreal_uproperty_CollisionProfileName _often_ but not always gets reset after reload. I'm using an HDA that generates two objects, with different properties, namely collision profile and collision complexity.
These properties will show up correctly when the HDA is first built (or rebuilt) but after save and reload they take what seems to be arbitrary new values.
Ultimately, we're trying to generate rather complex static mesh actors that are composed of different parts with different types of collision. We've found this impossible with this inconsistency. It would be very bad to have to recook all our HDA assets in UE every time we load a map.
Surprisingly I also tried these tests with the new Version 2 (alpha 2) of Houdini Engine inside 4.25.1 and similar problems occur.
I'm very eager to find a solution or even a workaround at this point.
EDIT: I wonder if this is an issue specifically with multi-mesh-component HDAs? I just tried the OneTonneBox and setting properties (like unreal_uproperty_Visible), saving, then reloading does seem to work fine.
EDIT2: Just tried OneTonneBox in 18.0.499 Engine and setting unreal_uproperty_Visible gets reset back to 1 after saving then reloading the map…so that's bad. Cooking the actor inconsistently reapplies the property correctly.

FWIW, I posted a cheapo python script that helps make the Curve tool a bit cooler here:
https://www.sidefx.com/forum/topic/53366/ [www.sidefx.com]

This is a poor substitute for a true fully-functional-multi-select Curve sop….
But below is a python script (“Curvify Edits”) I wrote that you can copy-paste into a shelf tool that is meant to be run when you're editing curves.
If you've multi-selected and are now editing your curve via an Edit SOP, it will copy all the point changes back into the Curve sop above it and delete the Edit SOP. Hit enter to insert or modify points or “s” to start selecting multiples again, laying down another Edit…which you can then Curvify later. I've bound it to a keyboard shortcut which makes it a decently smooth workflow.
It assumes you have a Curve sop followed by an Edit. It's nothing fancy, but it works for me and has alleviated much aggravation from my life.

I'm working on this same basic task and found that the instancing works with a UE Blueprint…
However, if I recook the HDA inside UE, 100% of the time the existing child BPs get disconnected and transforms reset.
I'd expect them to remain unchanged, since the HDA is unchanged, just recooked.
Do you (or anyone) see this issue as well?

UPDATE: Solved. Turns out the BP I was instancing had an internal component set to Static Mobility. This was fighting the parenting that only appeared on the re-cook. Switching the mobility cleared it up.

Unless I'm misunderstanding your setup, you need to provide the wall in which a hole will be cut as an input into Houdini as well.
Is this one of your world outliner inputs? You can't just provide the cutter to Houdini. It specifically needs both the cutter cube and target geo to be cut.

At our studio we are using the UE v1 plugin and have geometry generated from UE Splines wrapped inside BPs.
These go through a relatively complex HDA to create static geo.
I've noticed that it can happen that if spline points are modified rapidly across several Houdini Actors, it can hang the HAPI process and potentially crash UE.
It makes me wonder how the Houdini Engine plugin handles this case: lots of changes across multiple actors all happening before the engine can even finish processing one network change.
More importantly, are there known issues where this can lead to hangs/crashes? Some of our Houdini Actors use multiple splines and we've seen some crash dumps that suggest the arrays of input splines can get boggled between actors during processing, possibly resulting in the hang/crash.
Thanks for any thoughts.
-Len

Thanks for the ideas @dpernuit. That might be useful.
We are on UE 4.24.1 running plugin built against Houdini 18.0.391 and engine 3.3.2