chronx
Any idea why this is happening?

vfx_dli
I had the same problem.

Hmmmm. I've gone through my video and set that up again but it's not giving me any errors.

Is it only happening when you create a new module? What happens if you bypass that module in the stack? Is the HoudiniCache module input set correctly?

mikelyndon-sesi

chronx
Any idea why this is happening?

vfx_dli
I had the same problem.

Hmmmm. I've gone through my video and set that up again but it's not giving me any errors.

Is it only happening when you create a new module? What happens if you bypass that module in the stack? Is the HoudiniCache module input set correctly?

I seem to have found a mistake. The latest version I used: 4.25.0-13144385 + + + UE4 + release-4.25. In this version, the option of “namespace modifier add” is canceled. I can only add the subnamespace of Houdini through the “change namespacemodifier-custom” option. After modification, everything looks normal on the UI, but Niagara doesn't seem to know that this attribute is under houdinisubnamespace. I'm not sure if it's my mistake. I hope to get help. Thank you very much for your efforts.
I found the Houdini killifdead module you made, then I deleted the Houdini namespace of NID, and then I added the subnamespace of Houdini with the “change namespace modifier custom” option. Then the error occurred. The result of watching me add houdinnamespace on the UI is the same as before I delete your houdinnamespace

Even with that difference I'm still not getting an error on my side. I'm using the same version of 4.25, and set the namespace with “Change Namespace Modifer > Custom…”
Without a file or video showing the steps you're taking there's not much more I can do to help.

mikelyndon-sesi
Even with that difference I'm still not getting an error on my side. I'm using the same version of 4.25, and set the namespace with “Change Namespace Modifer > Custom…”
Without a file or video showing the steps you're taking there's not much more I can do to help.

I tried to verify the error in this way.
Did I do anything wrong?
Thank you very much.
https://drive.google.com/file/d/1BdaT2pX4wrez1byEkeyQlrGPFELqHECw/view?usp=sharing [drive.google.com]

vfx_dli
Did I do anything wrong?

Ah. You're naming the namespace HOUDINI. The correct namespace is “Houdini”. Uppercase “H”, lowercase “oudini”.
If you hover the mouse cursor over the particle attribute name, you can see the correct namespace.

mikelyndon-sesi

vfx_dli
Did I do anything wrong?

Ah. You're naming the namespace HOUDINI. The correct namespace is “Houdini”. Uppercase “H”, lowercase “oudini”.
If you hover the mouse cursor over the particle attribute name, you can see the correct namespace.

I'm so stupid. Thank you very much for your help.

Hi gang, I've been having a blast taking in particles from Unreal and playing with them in Niagara.

Most of what I've done so far has been generating procedural shapes in Houdini and exporting them as single frames, with particle counts up to 100k not being a problem (though of course this is heavy and intended for cinematic use more than gameplay.) Still getting framerates of around 60-120fps for basic animations, even stuff involving more computations like this:



So far use on the houdini side is intuitive and seamless, really learning how to use Niagara has been the only real challenge. My only question at the moment is what is meant by the “spawn group” value in the “Spawn particles from Houdini Point Cache?” This suggests I could have two caches to read from in a single emitter? Would be interesting to try to morph from one to another.

Early on I tried much more sparse pointclouds and tried to create the line-art look I'm after with ribbons, but ribbons seem fairly unstable at the moment and simply interpolating more particles got me to my look much simpler. I'd still love to see some kind of support for lines/wires so we could fake fabrics, splines etc but I'm not sure such a thing is even on the radar…

I will post updates on my progress on my blog here [andy.moonbase.net] and continue to experiment. Thanks for a very promising and useful initiative!

Hi friends!, One maybe noob question in that field, in the rocks example, there is a module called transient, and im trying recreate the hole effects but i cant find how set transient.PhysicsForce, the documentation dont say nothing about that too, how can i set that transient.PhysicsForce, and what is his function in the niagara system. Thanks for all the content guys, you are amazing!

Hi everyone,

i´m doodling with Houdini and Ue4 and got the demo´s above working, thanxx for the great videos which helps me to get started !!

Now i try to export some debris particles to ue4 but the problem is that
i it seems that i also got the points of my static-collision meshes exported, when i try to
import the hbjson into UE4, the result is a crash of unreal.

I added the “niagara-rop exporter-node” to my debris-dopimport-node, not sure if´s the right way todo.


When i deactivate the static-collision meshes in the debris-sim it seems to work(but my particles-sim is strangely rotated in ue4).

I´m new to houdini, i´m sure i do alot things wrong …
Any help would be nice

Bye, Andy

Hi Mike,
Ive been trying this amazing features and everything is working fine.
This is so great and thank you very much for the walk-through videos and example files.
It helped alots.

But I have a problem when I tried to capture my point cache niagara with sequencer.
When I hit play/simulate or play in sequencer, the niagara system worked fine.
But after I captured it ,the results seemed like all the niagara system is fast fowarding.

Any idea why this is happening? or should I ask this question to Epic?

Thanks again

hello,

I tried to use NiagaraSystem'/HoudiniNiagaraDemo2020/Niagara/NebulousSystem.NebulousSystem' on my map and cook it. ( I got some problems with cooking build with this plugin). It is working perfectly fine but when cooking I got this error:


LogInit: Display: LogNiagaraEditor: Error: Pin states that it is of class type, but is missing its class object. This is usually the result of a registered type going away. Pin Name ‘None’ Owning Node ‘/HoudiniNiagara/Modules/SpawnParticlesFromHoudiniPointCache.SpawnParticlesFromHoudiniPointCache:NiagaraScriptSource_0.NiagaraGraph_0.NiagaraNodeParameterMapGet_6’.

I checked in this script and on Get Point IDs to Spawn at Time there is function script with value: none. I cant figure it out honestly. What is supposed to be there? Or how to cook it?

MightyKaziu
It is working perfectly fine but when cooking I got this error:

Hi. We fixed this a couple weeks ago. When did you download the plugin?

You can try downloading the zip file again which should have the fix in it.

Otherwise, the solution is to recreate the SpawnParticleFromHoudiniPointCache module. If you just match everything 1:1 and replace it, it will work.

Mike

Hello,

I am getting a crash no matter what I try to open in the Demo2020

LoginId:df7633274c1c202ac2f75bb59099e2a9
EpicAccountId:92aaad9d542241059d3cbfdf0c1a6e15

Fatal error: Cast of nullptr to Class failed

UE4Editor_CoreUObject
UE4Editor_Niagara
UE4Editor_Niagara
UE4Editor_Niagara
UE4Editor_Niagara
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
user32
user32
UE4Editor_ApplicationCore
UE4Editor
UE4Editor
UE4Editor
UE4Editor
UE4Editor
kernel32
ntdll

Has anyone had this or understand what is going on?

Thanks for any help

Hi,

I've been having the same issue as MightyKaziu where the node isn't packing and returning the message:

LogNiagaraEditor: Error: Pin states that it is of class type, but is missing its class object. This is usually the result of a registered type going away. Pin Name ‘None’ Owning Node ‘NiagaraNodeParameterMapGet_6’.

I tried to follow Mikes advice to remake it but I'm getting a different error:

F3432E504638C117392D52B2D40809DE_SampleParticlesFromHoudiniCache_1_MessageLog: Error: Cannot Set external constant, Type: int32 Variable: Emitter.Houdini.MinIndex - Node: Map Set -

I downloaded the version of the plugin on the first page earlier today. Any idea what I can do to fix this?

Thanks

RichardS96
Hi,

I've been having the same issue as MightyKaziu where the node isn't packing and returning the message:

LogNiagaraEditor: Error: Pin states that it is of class type, but is missing its class object. This is usually the result of a registered type going away. Pin Name ‘None’ Owning Node ‘NiagaraNodeParameterMapGet_6’.

I tried to follow Mikes advice to remake it but I'm getting a different error:

F3432E504638C117392D52B2D40809DE_SampleParticlesFromHoudiniCache_1_MessageLog: Error: Cannot Set external constant, Type: int32 Variable: Emitter.Houdini.MinIndex - Node: Map Set -

I downloaded the version of the plugin on the first page earlier today. Any idea what I can do to fix this?

Thanks

I found a work around, the spawn from point cloud module wasn't actually needed so as long as you know how many particles you need then you can just use a normal burst spawn and just sample the positions/attributes like you would normally. Then delete the spawn module in the plugin folder and it packs.

Hi!
I'm trying to update the particles scale, color and orientation with the houdini attributes in niagara emitter over time.
I can get these attributes in particle spawn but I in the particle update, the values doesn't change.
Any suggestions?
Thanks!

MiguelVirgílio
Hi!
I'm trying to update the particles scale, color and orientation with the houdini attributes in niagara emitter over time.
I can get these attributes in particle spawn but I in the particle update, the values doesn't change.
Any suggestions?
Thanks!

By default, the SampleHoudiniPointCache module script does not update the pscale. You can double click on the module to view it and see that it differs from the SampleSpawnedHoudiniPointCache module by omitting this particular attribute sample.

Fixing this is pretty easy and I did it by just creating a new scratchpad module.


For more details on how to set this up, you can watch the “Sampling Custom Attributes” on the video tutorial page [www.sidefx.com]

Hey,I was wondering where have the impacts and splits gone in the Lab Niagara ROP?
I wanted to use in unreal engine to emit particles from my Houdini rbd sim.

903/5000
Hello everybody! Thanks for the great tips!

I need help, please: It's about blueprint interactions with Niagra systems. I am currently building a VR Dataviz.

I have this vellum grain simulation with 148,000 points. I successfully imported the animation of the point cloud into Unreal with Niagra. The spheres are rendered as sprites. The shader is just a flat, round disk with a normal sphere.

The animation runs real-time in unreal. The frame rate could be better but it works.

I would like to implement an interaction: When the VRPawn enters the holographic disk, the Niagara system should stop and pause at the highest point. As soon as the VRPawn is no longer in the hologram, the Niagara system should continue to run. Unfortunately I couldn't find any video on Youtube that could help me …

The video is rendered with Blender and is for viewing only. The last image is a screenshot form UE






Update: I figured out how to pause the system by entering a trigger volume. It works but is not reliable. Does anyone have any suggestions for improvement?

Furthermore, I would like to address a specific point in time within the loop duration (11.6s). For example, the system should pause at second 7. Right now it pauses right away the VRPawn enters the trigger volume.


Many thanks in advance

Hi there, I've been trying to build a setup that introduces multiple particle meshes - in Houdini I have an attribute ramp made with some noise that outputs a value of 0 or 1 across the entire mesh and called it parmesh.

In UE4 I've followed the tutorials about custom attributes and have managed to hook up parmesh to the color channel as well as the size to confirm that it's being read and works. What I'd like to do though is use it to also control one of two meshes that are rendered.

I tried using a custom sort descending on both mesh renderers and then changed the bindings on both to be Particles.Houdini.parmesh as per the custom attribute setup.

Unfortunately, it's showing both particles in the same place - I'm wondering is this the right way I'm going about it and missed something or if there's another way I should be approaching this?