Houdini Niagara Updates
63988 70 83- axess21
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Hi all. I'm trying to use the Houdini Niagara rop to bring an RBD simulation to Unreal and struggling in transferring the correct orientation for the pieces. Did anyone manage to achieve this?
I managed to create the correct orient attribute in Houdini, but how do I feed it to Niagara? What module should use this attribute? I tried “orient mesh to vector” with overriding the quaternion, but it gives the wrong orientation whatever I do.
edit - I found a solution - I had to generate a fake N from orient inside Houdini and export both orient and N, then I used this normal as Look at the direction in “orient mesh to vector” module + orient as quaternion override + N as reference axis vector + 1 override incoming orientation. This feels like an overly complex answer to a simple rotation question.
But I have new questions:
1 - Niagara side - When I try to convert emitter to GPU sim, I get an “invalid type for index in NiagaraEmitterInstance.ush”. Is it even possible to use GPU?
2 - Houdini side - After the first frame I have a weird position offset on each piece. I think it could be some pivot offset, but why it's only starting on frame 2? I mean It looks ok in sim right after RBD but if I delete geometry and instance exported pieces on rbd points, this offset appears.
I managed to create the correct orient attribute in Houdini, but how do I feed it to Niagara? What module should use this attribute? I tried “orient mesh to vector” with overriding the quaternion, but it gives the wrong orientation whatever I do.
edit - I found a solution - I had to generate a fake N from orient inside Houdini and export both orient and N, then I used this normal as Look at the direction in “orient mesh to vector” module + orient as quaternion override + N as reference axis vector + 1 override incoming orientation. This feels like an overly complex answer to a simple rotation question.
But I have new questions:
1 - Niagara side - When I try to convert emitter to GPU sim, I get an “invalid type for index in NiagaraEmitterInstance.ush”. Is it even possible to use GPU?
2 - Houdini side - After the first frame I have a weird position offset on each piece. I think it could be some pivot offset, but why it's only starting on frame 2? I mean It looks ok in sim right after RBD but if I delete geometry and instance exported pieces on rbd points, this offset appears.
Edited by axess21 - Nov. 6, 2020 05:27:22
- JacobAndersen
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Hi There
I am trying to create a looping particle animation and there seems to be a weird delay in the beginning of animation. I have reduced my data to 1 point and 10 frames and created a super simple position sampler, but the problem still presists.
In Particle Update my ‘Test Script’ just reads the position value of the particle 1 at frame 1 (the position is 0,0,0 here) and passes it on to the Houdini particle position parameter. But I have to go to approx. 0.03 on the timeline before the particle shows up.
WHAT am I not understanding here?!?
Cheers
Jacob
I am trying to create a looping particle animation and there seems to be a weird delay in the beginning of animation. I have reduced my data to 1 point and 10 frames and created a super simple position sampler, but the problem still presists.
In Particle Update my ‘Test Script’ just reads the position value of the particle 1 at frame 1 (the position is 0,0,0 here) and passes it on to the Houdini particle position parameter. But I have to go to approx. 0.03 on the timeline before the particle shows up.
WHAT am I not understanding here?!?
Cheers
Jacob
- Noboru_Garcia
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- ArtemiyLopyrev-Malatskov
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axess21
edit - I found a solution - I had to generate a fake N from orient inside Houdini and export both orient and N, then I used this normal as Look at the direction in “orient mesh to vector” module + orient as quaternion override + N as reference axis vector + 1 override incoming orientation. This feels like an overly complex answer to a simple rotation question.
I found a simple solution:
In “Orient Mesh to Vector”
1. Apply @up to ‘Look at Direction’
2. Apply @N to ‘Side Axis Direction’
- Josich
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- Dimitar Bonchev
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Hey,
awesome job with the NiagaraROP!
And a question. Can we use GPU simulations in Niagara with this setup? Currently, I'm receiving an error - Invalid Simulation.
/Engine/Generated/NiagaraEmitterInstance.ush(2234,18-152): Err0r X3120: invalid type for index - index must be a scalar, or a vector with the correct number of dimensions HoudiniNiagaraBasic, Particle GPU Compute Script,
/Engine/Generated/NiagaraEmitterInstance.ush(1752,2-29): warning X3206: implicit truncation of vector type HoudiniNiagaraBasic, Particle GPU Compute Script,
Thanks
awesome job with the NiagaraROP!
And a question. Can we use GPU simulations in Niagara with this setup? Currently, I'm receiving an error - Invalid Simulation.
/Engine/Generated/NiagaraEmitterInstance.ush(2234,18-152): Err0r X3120: invalid type for index - index must be a scalar, or a vector with the correct number of dimensions HoudiniNiagaraBasic, Particle GPU Compute Script,
/Engine/Generated/NiagaraEmitterInstance.ush(1752,2-29): warning X3206: implicit truncation of vector type HoudiniNiagaraBasic, Particle GPU Compute Script,
Thanks
- liua
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- simco50
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Any update for 4.26 is appreciated. It's been released for quite a while now and the Git repo hasn't been updated for a couple of months. Epic seems to have removed the plugin in the Unreal Engine repo likely because of compatibility reasons but it is problematic for projects depending on this plugin.
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- Noboru_Garcia
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When I try to add forces to the cached simulation as is sown in some of the demonstrations each loop gets more and more distorted and the particles begin to jitter around. I am using the default Houdini Basic picking my Point Cache and then putting a noise, everything looks and works fine until I use a noise to add a little variation. I have also noticed that each loop doubles the number of points. Is there something more I should be doing? What is the correct setup to have?
UPDATE FIXED
It's worth mentioning that if a sim needs to loop they should be killed before the end of the exported cache's last frame or pad the loop beyond the lifespan. I think when Niagara injects more particles and looses track of ID's.
UPDATE FIXED
It's worth mentioning that if a sim needs to loop they should be killed before the end of the exported cache's last frame or pad the loop beyond the lifespan. I think when Niagara injects more particles and looses track of ID's.
Edited by Noboru_Garcia - Aug. 31, 2021 17:08:18
- “spooky action at a distance”. Albert Einstein
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