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Found 113 posts.

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Technical Discussion » HDA parameters disappear

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coccarolla
113 posts
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 June 13, 2025 02:46:10
Jonathan de Blok
I guess you might have added parms through the 'edit interface' button. For HDAs you need to uses 'edit type' and then go to the interface tab.

The difference is that the first method only adds parms to that specific instance of a node, the second method actually makes it part of the HDA asset.

Thanks!
I'm pretty sure I'm adding them via type properties though. One strange thing I am noticing is that sometimes when I close and reopen the file the definition appears as embedded. The frustrating part is I can't find a logic to it... if I do apparently random things with the hda or the file and warnings I sometimes get the parameters back and can continue to work... I would really like to for it to make more sense!
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Technical Discussion » HDA parameters disappear

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coccarolla
113 posts
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 June 12, 2025 07:23:12
I'm trying to create an HDA, just leaerning for personal use, and it is now at version 1.4, with a dev prefix.
The problem I am having is that the parameters are all gone when I reopen the file.

Sometimes it works to switch the path from 1.4 to embedded and back to 1.4 and that sometimes re-populates the parameters but this is very inconsistent and really not what I would want.

I always do a save node type when I edit the parameters.

PS: I also have a lot of errors when starting Houdini because of this hda, and the only thing special I'm doing with it as far as I can tell is loading a handle from a python module.
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Houdini Lounge » 3D Connextion space mouse with Houdini

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coccarolla
113 posts
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 June 4, 2025 05:00:05
a5af
You can think of the SpaceMouse not like a mouse, not like a game controller, but exactly like 1970's-era NASA docking controller on a space shuttle.

The control is:
Nonlinear,
Sensitive,
Counterintuitive, at first.

But real astronauts train to dock a module — where a wrong nudge means catastrophic failure.

The trick is not to fight it, but to reprogram your instincts.
You will start anticipating unnatural movement, strange drift, the backward lag, and the disorganized momentum — until your brain adapts, until the movement becomes second nature.

It must become second nature — because when you're controlling a spaceship (or a 3D object in Houdini), hesitation or overcorrection is not an option.

Master the drift. Master the tilt. Or crash and burn.

I thought I'd contribute my work to this effort.

Attempts So Far — 3Dconnexion SpaceMouse → Houdini Integration (with Tilt Correction)
1. Basic SpaceMouse → Houdini Setup
Installed 3Dconnexion drivers.

Confirmed SpaceMouse works outside Houdini (in viewer mode, etc.).

Houdini does recognize 3D input, but by default it’s camera-only — not tied to scene objects.

2. Custom Python Panel / Script Approach
Wrote custom hou.session or panel Python to hook into SpaceMouse input.

Problem: spacenavigator module dependency failed — not native to Houdini's shipped Python.

Tried pip installs inside Houdini — Python incompatibility (spacenavigator not available or crashes Houdini Python).

3. HID (Human Interface Device) Layer Attempt
Tried low-level raw HID access.

Success reading input outside Houdini, but no bridge between raw input and Houdini’s viewport transformations.

Writing a full input device driver → too much overhead unless embedding into the viewport.

4. 3Dconnexion SDK Direct Integration
Tried using 3Dconnexion SDK.

Problem: SDK is C++, not Houdini Python-friendly.

Need custom C++ plugin compiled against Houdini API — basically writing a custom OP, impractical for now.

5. Matrix Math Tilt Correction
Attempted to apply tilt correction:

Read rotation matrices.

Tried to extract "up" vector and re-orient.

Problem: Houdini's Matrix3 class missing methods like getRow3, extractRow (non-existent).

Correct tilt math needs more low-level matrix operations not exposed in Houdini's Python API.

6. Use of Default Houdini "Lock Horizon"
Tested Lock Horizon mode inside Houdini viewport.

Outcome: Partially corrects tilt, but not reliable in extreme rotations.

7. Fallback to 3Dconnexion System Settings
Modified global SpaceMouse settings (e.g., lock axes, lower sensitivity).

Better control overall — but still no native scene manipulation inside Houdini objects.

Next Possible Moves
Option 1: Custom C++ Houdini Plugin
Write C++ plugin using Houdini HDK.

Map SpaceMouse input directly to object transforms (NOT viewport camera).

Cost: Huge. Need to build and maintain.

Option 2: Use Intermediary Software
Use something like TouchDesigner, Blender, or custom app that reads SpaceMouse and sends data to Houdini via:

OSC (Open Sound Control) messages.

TCP/IP or websockets.

Houdini reads live input stream and transforms objects accordingly.

Option 3: Python PyWin32 Hook (Windows Only)
Poll for SpaceMouse via PyWin32 raw input stream.

Map to Houdini objects manually.

Option 4: Surrender to the Camera, Not Objects
Fully embrace controlling only the camera.

Build rigs or scripts to align view-based interaction to object placement after motion.

My god, sir! Did you write this with ChatGPT?!
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Technical Discussion » Python Interactive Viewer State Handle = Resources regist...

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coccarolla
113 posts
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 May 27, 2025 12:08:01
I am trying to build an hda using a handle an viewer states. The code for the handle is created on a node inside that hda, and on the hda itself I have the code for the viewer state. However using this setup I am having this error at startup, when Houdini starts with an empty scene:

= = = Resources registration = = =
ERROR: ..._generator::1.0 cannot use handle 'testhandle' because it is not a handle type.

I also note constant crashes, but especially when I want to edit the type properties of the hda, more notably the parameters tab.
Can anyone please help me figure out what the problem is, or if the problem is the setup itself what can I do about it in that case?!

Edit: the error itself at the moment of crash looks like this:
Creation of unknown handle type testhandle
23296: Fatal error: Segmentation fault
Saving application data to
Edited by coccarolla - May 27, 2025 12:22:35
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Technical Discussion » Python Interactive Viewer State Handle problem / question

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coccarolla
113 posts
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 May 18, 2025 07:21:18
I'm trying to learn python states and I am building a small tool, so far it looks something like in the screenshot.

I have a problem I stumbled upon accidentally: if hit ' on the keyboard (which apparently is the shortcut for handle detachment) the handle detaches permanently. The tool will not work again, unless I copy the HDA.

I guess I should ask: is there a way to disable detachment for this handle? Or maybe: is there a better way to build this handle in the viewer states, like using a gadget or something (I would like the handle thickness to match the white line)?


Edited by coccarolla - May 18, 2025 07:22:34
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Technical Discussion » Configure VSCode for Python (IntelliSense, code completion,

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coccarolla
113 posts
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 May 13, 2025 13:32:53
pakreht
Hello everyone, i have just finished writting my first article, it explain in detail how to set up your Visual Studio Code so you have full intelliSense for Python in Houdini, i think it can be usefull for a lot of people so i've put my heart to it •ᴗ•

You can check it just right here : https://pakreht.com/houdini/configure-vscode-for-python/ [pakreht.com]

If you follow throught you should end up with something like this :


Don't hesitate to give me feedback and ask for clarifications on some aspects ಠ‿<

Just found this. Set everything up, including the stub linked on the blog. I'm not sure it works correctly. The code looks nothing like in your gif, and I still get this 'any'. Can you give any hints?

Edited by coccarolla - May 13, 2025 13:33:44
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Technical Discussion » Python States Handle Documentation

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coccarolla
113 posts
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 May 12, 2025 17:25:49
Where could I find all the settings and their functionality that I can use here?
I'm browsing the docs but going in circles with no info.

Edited by coccarolla - May 12, 2025 17:25:58
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Technical Discussion » Python Interactive Viewer State Handle orientation problem

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coccarolla
113 posts
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 May 12, 2025 14:49:42
I'm trying to build a python states interactive handle and I want to orient a handle to the normal of different primitives. However I don't understand how to correctly orient the handle. In the viewport it appears correct but the values extracted from the handle are not correct. For example in this image the RY of the gives weird values:
Image Not Found

Basically here when I rotate RY in the viewport the actual value from the handle is RZ, or RX -depending on the normal value. It's like there is a different, internal orientation of the handle.
Edited by coccarolla - May 12, 2025 14:50:41
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Technical Discussion » Example scenes in $HFS/viewer_state_demo/ do not work

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coccarolla
113 posts
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 May 2, 2025 15:52:28
alexmajewski
You should probably submit a bug report on the main website. I was able to get that scene working by manually installing the required HDA that the error is talking about.

Those HDAs seem to be located in $HFS\packages\viewer_state_demo\otls, simply install them locally inside the HIP.

Thank you very much! I'll try your workaround.
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Technical Discussion » Example scenes in $HFS/viewer_state_demo/ do not work

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coccarolla
113 posts
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 April 30, 2025 03:14:08
Can someone tell me if I'm understanding wrongly the purpose of these scenes?
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Technical Discussion » Example scenes in $HFS/viewer_state_demo/ do not work

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coccarolla
113 posts
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 April 25, 2025 13:35:47
Not a single example file works from this folder. I have tried opening them in Houdini 20.5.578 Py3.11
Most of them have errors on open. Is there something I am doing wrong?
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Houdini Indie and Apprentice » Set external script editor not working

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coccarolla
113 posts
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 April 23, 2025 03:53:17
Andrew Graham
jomaro
I am having the same issue even in H20.5, everytime you open the external editor you need to close the file in VSCode to prevent Houdini from crash!

did you use -w like I suggested?

Is this the only solution? Having to close the file and reopen constantly is no fun...
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Houdini for Realtime » Artists' Guide for External Editor for Scripting in Houdini

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coccarolla
113 posts
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 April 23, 2025 03:33:33
I'm having trouble setting this up. I've defined Sublime both as EDITOR and as VISUAL in the houdini.env file. But I can't get it to work properly from within Houdini.
For example: in the case of wrangles the keyboard shortcut doesn't work, or even if it launches the editor then changes and saving from Sublime will not work. But if I right click the vex editor and select from the menu Expression > Edit in external editor Sublime will work. It gets even more weird if I try to setup a shortcut for python editor.
I'm not sure what to try next.
Edited by coccarolla - April 23, 2025 03:34:11
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Houdini Lounge » Measure SOP Useless Controls?

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coccarolla
113 posts
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 April 15, 2025 08:55:30
I will answer my own question here in order to spare anyone else the trouble.

The confusion for me arose expecting a similar toggle like in other places in Houdini.
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Houdini Lounge » Measure SOP Useless Controls?

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coccarolla
113 posts
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 April 15, 2025 05:38:01
What is the point of this section in the Measure SOP?

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Houdini Lounge » Curve Select/Edit Not Snapping to Self

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coccarolla
113 posts
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 April 14, 2025 03:33:13
CYTE
Yes, they do. You have to enable point snapping.

Cheers
CYTE

Here is a screen of my snap settings. The points do not snap no matter what I do. I am starting with a polygon curve, if that counts.
Edit: also have Vulkan enabled... I've been hearing there might still be some bugs with it
Edited by coccarolla - April 14, 2025 03:34:59
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Houdini Lounge » Curve Select/Edit Not Snapping to Self

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coccarolla
113 posts
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 April 14, 2025 02:54:44
Simply put, when creating / editing a curve the points do not snap to self.

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Technical Discussion » FBX Export Groups / Primitives as Separate Objects

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coccarolla
113 posts
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 April 10, 2025 04:29:19
willh
here is the setup im currently using, it works pretty well. Everything is instanced in unreal without me having to do anything except click build in unreal on the hda
This looks pretty dope? Can you breakdown a little what and how you're doing?!
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Houdini Lounge » 3dsmax unwrap spline map in Houdini

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coccarolla
113 posts
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 April 2, 2025 05:18:04
Aizatulin
Have you tried labs uv-transfer?
Input:
1.any spline like object
2.corresponding spline

create a clean sweep from the spline with uvs and use uv-transfer.

This is quite handy. Thanks!
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Houdini Lounge » 3dsmax unwrap spline map in Houdini

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coccarolla
113 posts
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 April 2, 2025 03:57:54
eikonoklastes
See if this works for you:

I don't believe so. I am working with cad models, so I don't see how it would help.
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