Attached is a minimal example, using H21.0.466, for the community that I would have found helpful myself.

Requirement: Need to "group" work items together for processing together, without partitioning.

Reasoning: Avoiding needing to wait until all upstream work items are complete to "group" them together. Depending on the situation, not using partitioning could be advantageous if you don't want to bottleneck your graph.

Note: I'm muddling through this stuff. There probably is a better way to pull this off. If you know if a better way, please post it up and add to the conversation.

Hello,

I have the code to set the IPRViewer colorspace when Houdini starts:


However, if the artist creates a new one it reverts to the default and the default might change depending on the project.

Is there a callback or way to set this on creation?

Many thanks in advance.

Hello ! i m searching an option for import a .shp file in houdini

Thx

Antoine

I am working with PDG to generate a large number of instances, but I am facing GPU memory issues even though the scene complexity is relatively moderate. Are there recommended strategies to optimize GPU usage in this context, or alternative workflows better suited for handling large simulation workloads?

Blenderでカメラトラッキングを行ったカメラをHoudiniにインポートしてKarmaでレンダリングを行いたいのですが、abcファイルで買いだした場合カメラの位置情報はSOP内に読み込めるのですがそれをSolarisでカメラとして認識する方法がわかりません、またusdファイルで書き出してからHoudiniに読み込もうと思ったのですがこの場合、Stage階層のノードで読み込むノードがどれかわかりません。どうすれば効率よくBlenderのカメラデータをKarmaで使用することが出来ますか？（カメラの設定や焦点距離も引き継ぎたいです）

How do I install these plug-ins externally outside of Launcher if they're not showing up?

Hi i am newbie. I just installed houdini with sideFXLabs(21.0.440) and i wanna use tree generator but my houdini dosen't show tree generator but some labs node is showing. what should i do? thanks.

KineFX often whinges when skeletons are cyclic ("Cycle Detected" errors). There's a good section on CGWiki [www.tokeru.com] to fix this, but it only works if there truly aren't cycles.

If the skeleton actually has cycles, you need to detect and repair them. I made a HDA for this purpose (I'm not sure why this isn't built into Houdini to be honest)

It can mark, split or remove cycles. Marking cycles can help for other graph traversal problems too.


Download here:
https://github.com/MysteryPancake/Houdini-Fun/tree/main?tab=readme-ov-file#hda-repair-cycles [github.com]

I’m running into a problem when using my HDAs in Unreal Engine 5.6 with Houdini 21.0.
When I drop my HDA into UE, none of the nodes seem to process at all. The only way I can get results is if I enable Session Sync and then recook inside UE.

Has anyone else run into this, or know if something changed in the way cooking is handled?

https://www.sidefx.com/docs/houdini/nodes/vop/kma_curvature.html [www.sidefx.com]

This node type is deprecated.
Karma Curvature is no longer supported, please pre-compute a primvar and import.
(Since version 21.0.)

Hi I am trying to carve a curve at corner points...
the goal is make a bend with a set inside radius

ok so I cut out a straight line from a corner so a bit like a chamfer but it is sized using some vex and carved to size by the geo's width and what ever size internal radius is wanted. And I basically create a three point ark.

for this to work the length from the corner point needs to be cut equally ether side or the ark will be bumped off line or not blend in well leaving a sharp edge allowing geo to overlap again.

The PROBLEM comes when bends are too close to each other not allowing enough geo on one side for the correct sizing.

Originally I was thinking to split the failed bends and do a second pass but this was not the fix. so now I believe that I need too carve the tightest bend first re-check angles to see if any nearby registered bends are still there or has the first carve cut it away and do the next bend until all required bends are made. I was using for each named prim before but the new idea has made my brain leave the building as it is trying to work out how to do all this in one wrangle node.

Hello

I'm wondering if the "dual LPE" syntax described in the OSL docs is supported in Karma? (I wasn't able to get it to work)

OSL Light Path Expressions [github.com]

Good, you got your alpha channel as a separate AOV, but what if you want to put it in the actual alpha channel of an RGBA AOV? You can do that by appending your expression to the standard rgb expression for an AOV. Look at this example:

Output ("beauty.tif", "rgba", "C[SGs]*D*<Ts>*L !C<Ts>*B")

初心者です、紙吹雪をテストで製作していました
地面に接した時に地面のノーマル方向に角度を変える（突き刺さらないようにする）挙動をやってみたかったんですが


上記popwrangleをpostsolverに繋ぐと最初からY軸方向を向き続けます
geometry Spread sheetを見てもhitnumの挙動は正しいように見えるんですが、全フレームでif文が発火してしまっているように見えます
根本的な所で勘違いをしていると思いフォーラムに投げさせて頂きました

お手数おかけしますが、ご助言いただけると幸いです

Ongoing issue with support but basically in most of my test having default caching enabled on pyro block end makes it completely unusable. Eg live sim or flipbook with caching disabled 150 frames approx 8-10 min. Turn on caching (the default) and it will take 30 min just to get to frame 50.

This is on windows 11 (all updated) with latest studio nvidia drivers and 3090 RTX 24GB

So to get the speed as weird as it sounds - disable caching on the pyro block end when working with pyro.

Hey guys,

I've recently ran into a set of GPU-related crashes when trying Copernicus (File, Constant COPs) and OpenCL SOP nodes. It looks like, though not a solution, there's a workaround, which hopefully may be solved in the future if SideFX decides to support Intel GPUs:

Add the following 2 lines into your Houdini start script:


I hope that may help somebody in the future.

Cheers!

NOT SOLVED YET :
the solution i found , not works if the previus asset has scale transformations too.
I will make another post flagging this error , with better info and explanation.
If you check on the toogle "local transform" , it fix the problem

Short Summary

Stage Manager becomes unusable if assets already have transforms. This makes it impossible to use Stage Manager reliably in layout and set dressing, breaking the most common USD workflows. The problem has existed since 20.5 and is still present today.

Detailed Explanation
Why this matters

Solaris is designed to be a complete USD workflow, from asset creation to final render. But right now, the Stage Manager — which should be the central node for layout and set dressing — only works once. As soon as you try to reuse it downstream on assets with pre-existing transforms, pivots and transforms break.

This is a show-stopper for production pipelines. Both small and large studios hesitate to adopt Solaris as their base pipeline because of this limitation. Without a reliable Stage Manager, teams are forced into awkward workarounds (dressing in SOPs with point imports, or building in-house tools) instead of using Solaris as intended.

Steps to reproduce (3 simple cases)

Case 1

Create a test rubbertoy in Solaris.

Apply scale/rotation/translation.

Add Stage Manager → move or duplicate → transforms break.

Edit LOP works correctly in the same situation.

Case 2

Create rubbertoy.

Add Stage Manager → move/duplicate/rotate.

Add another Stage Manager → pivots/positions become corrupted again.

Edit LOP still behaves correctly.

Case 3 (real production scenario)

Layout department publishes blocking with Stage Manager (placing assets, variants, transforms).

Set dressing department loads that opinion and tries to refine or duplicate assets.

Stage Manager fails — transforms break because layout already added transforms.

Result: impossible to refine layout with Stage Manager in set dressing.

Why fixing this is critical

Stage Manager should be the main tool for layout and set dressing in Solaris.

Without it, Solaris cannot be used as a full USD pipeline.

Forcing workarounds discourages adoption: some studios move dressing to SOPs, others avoid Solaris altogether and stick with Maya.

Fixing Stage Manager would unlock Solaris as a robust USD pipeline tool, not just a lookdev and rendering playground.


Attachments

.hip file demonstrating the bug

Video showing the issue step by step



Do you also encounter this issue in production? I’d love to hear your experiences — the more visibility this gets, the higher the chance of a fix.

Thanks!!!!
best regards!!

Sometimes you need to deform an object inside another with respect to the internal volume, for example muscle inside a body.


One way is converting the object to tetrahedrons, since tets have 3D primuvw coordinates for interpolation. Sadly this isn't always an option, because the triangulation changes when animated.

A better approach is using Positive General Mean Value Coordinates (PGMVC), as implemented many years ago by Sibbarick [forums.odforce.net].


It works by casting rays in a sphere from each point, creating lines. Each line acts as a distance constraint, pulling the point as the walls move. It's almost like Point Deform with occlusion, where only the faces visible to a point light are used for deformation.


I rewrote Sibbarick's method using primuv to make it simpler, with slightly better results on the exterior.

Download here:
https://github.com/MysteryPancake/Houdini-Fun/tree/main?tab=readme-ov-file#hda-volumetric-deform [github.com]

Hi All! I'm working in H20.5 (can't wait to get to H21 but I'm on MacOS M-Series systems and it'll be a while before Otoy gets around to getting a H21 build for me . I have just a simple question that seems like it should have a very simple and obvious answer but I'm struggling. So, I have a very simple APEX humanoid rig with FK and IK and controls. I would like to add noise to a keyframe animation (or the complete animation) via CHOPS nodes. But I just can't figure out how. I've tried many approaches. Any help would be greatly appreciated!!!


Thanks,
Greg

I have first node with 1000 points (no more attributes)
I have second node with 2000 points (no more attributes)

And I change some of these points in std::thread

And I have third node - Merge - first + second

How I can receive these points from Merge node? HAPI say, what there are 0 parts and 0 geos in Merge node.
How Merge Node saving all points and how I can get it in HAPI?

Houdini Session showing correct values in Geometry SpreadSheet. How I can show such points table in my own app?

Is anyone having trouble getting material instance parameters working? Wondering if this is a user error or a bug.

I'm following the documentation, but can't get the "unreal_material_parameter_diffuseboost" param values to transfer over like in the example. My material instance is being created fine, however.

https://www.sidefx.com/docs/houdini/unreal/materials.html#instances [www.sidefx.com]