Hi TOPpers,
I have a basic-ish question:
I am trying to make a library of snowflakes using Entagma's tutorial.
The setup uses a SOP Solver to ‘grow’ the shape and outputs poly geometry.
I want to save out the GEO as BGEOs at the end of a 100 frame sim,
but I want to do this a number of times with random values in the sim's various parameters.
I have worked out the wedging part of the TOP network, but I really don't want to save the
GEO for every frame, just the end frame.
So, is there a way to save out the GEO at frame 100 ONLY.
Could it be something to do with those ‘partition’ nodes?
I can't make much sense out of them and they all look like they do the same thing.
Usually just writing a post on this forum will get things straight in my brain,
but that has not happened yet, so I'm hitting the ‘post’ button.
Thanks for your help!
Dan
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PDG/TOPs » Saving ROP geometry at end of simulation
- dansidi
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Houdini Indie and Apprentice » overriding display option (wireframe)
- dansidi
- 59 posts
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Nicolas Heluani
To whom it may help apparently I overlooked that you can effectively override display options for specific elements and selection on a scene under the display option marker tab There you can set display options for Scene Geometry, selected Scene geometry, current model geometry, etc. Is not the same but it works for my objective.
Hi Nic,
Where can I find that display option marker tab thing?
Thanks!
Technical Discussion » Crashing in 16.5 using Crowd sim - cannot re-open hip file!
- dansidi
- 59 posts
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Technical Discussion » Crashing in 16.5 using Crowd sim - cannot re-open hip file!
- dansidi
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BabaJ
I then switch the cook setting to Manual and save the file.
Thanks, BabaJ.
How can I switch the cook setting to ‘Manual’?
I'm in 16.5
Many thanks,
D.S
Technical Discussion » Crashing in 16.5 using Crowd sim - cannot re-open hip file!
- dansidi
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Hi all,
I wonder is anyone else is having the problem I am experiencing:
I have a simple crowd sim:
1. I have one agent defined from a FBX. The agent is generated in a different hip file and baked out. In my simulation scene, I am accessing the agent from ‘disk’
2. I plug this agent into the crowd source node.
3. I simulate my crowd source, using the shelf tool. All good so far.
4. I have some geometry (waving flag) saved out as a bgeo sequence, which is brought into my crowd system as packed primitive sequence. It is then attached to my simulated agent with the Agent Relationship node.
5. I save the scene.
6. When I press play or try to cache out my geometry, I get ‘segmentation fault’, Houdini bombs out and I can not load my scene any more. Not only that, I cannot load the backup scene or even any other scenes I have ‘saved_as’ along the way. As soon as I try to load a hip file, I get a segmentation fault again and Houdini bombs out. Weird.
I have remade my agent (with new name) from scratch and remade my simulation scene multiple times and this crash keeps happening.
Has anyone seen this kind of problem? What can I do to recover my hip scenes
I wonder is anyone else is having the problem I am experiencing:
I have a simple crowd sim:
1. I have one agent defined from a FBX. The agent is generated in a different hip file and baked out. In my simulation scene, I am accessing the agent from ‘disk’
2. I plug this agent into the crowd source node.
3. I simulate my crowd source, using the shelf tool. All good so far.
4. I have some geometry (waving flag) saved out as a bgeo sequence, which is brought into my crowd system as packed primitive sequence. It is then attached to my simulated agent with the Agent Relationship node.
5. I save the scene.
6. When I press play or try to cache out my geometry, I get ‘segmentation fault’, Houdini bombs out and I can not load my scene any more. Not only that, I cannot load the backup scene or even any other scenes I have ‘saved_as’ along the way. As soon as I try to load a hip file, I get a segmentation fault again and Houdini bombs out. Weird.
I have remade my agent (with new name) from scratch and remade my simulation scene multiple times and this crash keeps happening.
Has anyone seen this kind of problem? What can I do to recover my hip scenes
Edited by dansidi - Nov. 23, 2017 06:18:40
Houdini Learning Materials » How to use custom per point attributes in DOPs
- dansidi
- 59 posts
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Hi,
Can anyone help me get the width attribute form an l-systems tree into the wire solver?
The wire object seems to show that it has a width attribute, but it had a value of zero.
I want to feed the width value from the l-system into the width field on the wire object.
Is this even possible?
Many thanks if you can help me.
Can anyone help me get the width attribute form an l-systems tree into the wire solver?
The wire object seems to show that it has a width attribute, but it had a value of zero.
I want to feed the width value from the l-system into the width field on the wire object.
Is this even possible?
Many thanks if you can help me.
Edited by dansidi - May 26, 2017 06:46:28
Technical Discussion » Varying Wire solver along L-System length?
- dansidi
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I can see that you can generate point attributes when the L-System is created, which gives a couple of useful sounding attributes: gen and width.
How would it be possible to feed these into the Wire solver?
Let's say I wanted to multiply Elasticity or Angular Damping by that width attribute. Can that be done? How can I do that?
Any help at all would be very gratefully recieved.
Thanks!
How would it be possible to feed these into the Wire solver?
Let's say I wanted to multiply Elasticity or Angular Damping by that width attribute. Can that be done? How can I do that?
Any help at all would be very gratefully recieved.
Thanks!
Edited by dansidi - May 26, 2017 07:00:23
Technical Discussion » Varying Wire solver along L-System length?
- dansidi
- 59 posts
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Hi everyone,
Well, I am still working on the shot where trees bend due to a rocket exhaust. I have tried FEM but I think it will not do what I want (too ‘chunky’).
I would like to try the Wire solver. What I want is the trunk of the tree to bend very slightly, the branches to bend a bit more and the twigs to bend a twitch a lot - bend angle proportional to branch thickness, basically.
How can I vary the wire deformer strength or bend angle along the length of the L-System branches? I suspect this is a VERY simple thing for a Houdini TD to do, but I am not sure how to approach it. Please help!
I enclose a simple setup where I have a L-system, converted into a Wire sim, with a hard pin constraint on the base of the trunk and I made a Wind force pushing on it.
Many thanks
Well, I am still working on the shot where trees bend due to a rocket exhaust. I have tried FEM but I think it will not do what I want (too ‘chunky’).
I would like to try the Wire solver. What I want is the trunk of the tree to bend very slightly, the branches to bend a bit more and the twigs to bend a twitch a lot - bend angle proportional to branch thickness, basically.
How can I vary the wire deformer strength or bend angle along the length of the L-System branches? I suspect this is a VERY simple thing for a Houdini TD to do, but I am not sure how to approach it. Please help!
I enclose a simple setup where I have a L-system, converted into a Wire sim, with a hard pin constraint on the base of the trunk and I made a Wind force pushing on it.
Many thanks
Edited by dansidi - May 25, 2017 08:46:19
Technical Discussion » Pushing FEM objects with Pyro
- dansidi
- 59 posts
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Thanks, Sidenimjay.
Yet another learning day with Houdini.
Can you think of a more procedural way of choosing the vertices for the constraint on the base of the tree? I just used a Group node to generate the vertex numbers and then copied and pasted those numbers into the constraint node. Not very Houdini-esque… I couldn't see a way to plug the Group node into the constraint.
Many thanks again.
Dan
Yet another learning day with Houdini.
Can you think of a more procedural way of choosing the vertices for the constraint on the base of the tree? I just used a Group node to generate the vertex numbers and then copied and pasted those numbers into the constraint node. Not very Houdini-esque… I couldn't see a way to plug the Group node into the constraint.
Many thanks again.
Dan
Technical Discussion » Pushing FEM objects with Pyro
- dansidi
- 59 posts
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Hi Sidenimjay,
Thanks so much for your message. Unfortunately I don't have H16, so I can't test your scene file, however I will try what you suggested and report back.
Can you give more info how to use the vector field visualisation DOP. I have attempted to set that up but couldn't work it out. Please could you post a screen grab of your vector field visualisation DOP, how it is plugged in and how it is configured. That would help me enourmously.
Many thanks!
Thanks so much for your message. Unfortunately I don't have H16, so I can't test your scene file, however I will try what you suggested and report back.
Can you give more info how to use the vector field visualisation DOP. I have attempted to set that up but couldn't work it out. Please could you post a screen grab of your vector field visualisation DOP, how it is plugged in and how it is configured. That would help me enourmously.
Many thanks!
Technical Discussion » Pushing FEM objects with Pyro
- dansidi
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Many thanks go to Paul from the Odforce forum.
He show that by using the SOPsolver node, which, I think, reads
data from another source and brings it in to the DOP network.
My understanding is very patchy, but I did get the system to work.
I enclose a working setup and render.
He show that by using the SOPsolver node, which, I think, reads
data from another source and brings it in to the DOP network.
My understanding is very patchy, but I did get the system to work.
I enclose a working setup and render.
Technical Discussion » Pushing FEM objects with Pyro
- dansidi
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Thanks again, Marco, but sadly it's not working.
Are you saying that I got the connections correct?
Are you saying that I got the connections correct?
Technical Discussion » Pushing FEM objects with Pyro
- dansidi
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Technical Discussion » Pushing FEM objects with Pyro
- dansidi
- 59 posts
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Hi Marco,
Thanks for your reply. I have tried your method, but I am unsure how to get the SOP Vector Field to read the cached pyro sim. How is that done? I see a slot called SOP Path – is that it? – what do I put in there?
I have tried pointing it to the Import_Pyrofields node, but it does not seem to do anything.
I have tried cranking up the force ( to -10000 or 10000) but without any effect on the FEM objects.
Thanks for your help. Nearly there, I hope.
Thanks for your reply. I have tried your method, but I am unsure how to get the SOP Vector Field to read the cached pyro sim. How is that done? I see a slot called SOP Path – is that it? – what do I put in there?
I have tried pointing it to the Import_Pyrofields node, but it does not seem to do anything.
I have tried cranking up the force ( to -10000 or 10000) but without any effect on the FEM objects.
Thanks for your help. Nearly there, I hope.
Technical Discussion » Pushing FEM objects with Pyro
- dansidi
- 59 posts
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Hi everyone,
I am a new Houdini user, coming from a Maya background.
I am working on a shot where a rocket is lifting off and the exhaust fumes will be affecting trees nearby.
I have made some trees using L-systems and I have been using FEM simulations to get the trees to bend using a magnet force. Also, I created the pyro sim for the rocket exhaust.
Is there a way to connect these two simulations so that the rocket exhaust causes the trees to bend?
Of course, I know there will be a way, but I could use some help getting these two simulations connected.
Many thanks.
Dan
I am a new Houdini user, coming from a Maya background.
I am working on a shot where a rocket is lifting off and the exhaust fumes will be affecting trees nearby.
I have made some trees using L-systems and I have been using FEM simulations to get the trees to bend using a magnet force. Also, I created the pyro sim for the rocket exhaust.
Is there a way to connect these two simulations so that the rocket exhaust causes the trees to bend?
Of course, I know there will be a way, but I could use some help getting these two simulations connected.
Many thanks.
Dan
Technical Discussion » per-particle attributes from Maya nParticles to Houdini via Alembic
- dansidi
- 59 posts
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… and here is the solution provided b y SASHO78 from Sofia.
in an Attribute Wrangle, directly after the Alembic node, add the following
So, we are creating a vector array, rgb
I think the prim function looks to the primitive context and fetches some data from there.
fetches rgbPP from the 0'th element in the 0'th input of the Attribute wrangle node (I think) and then assigns that data to an vector array called rgb
creates a vector called Cd and then looks up the @ptnum'th value of the array rgb and copies it to Cd.
Very useful. I with I had thought of it, but ALL the credit goes to Sasho78.
Thanks a lot!
in an Attribute Wrangle, directly after the Alembic node, add the following
vector rgb[] = prim(0, "rgbPP", 0);
v@Cd = rgb[@ptnum];
So, we are creating a vector array, rgb
I think the prim function looks to the primitive context and fetches some data from there.
vector rgb[] = prim(0, "rgbPP", 0)
v@Cd = rgb[ @ptnum ]
Very useful. I with I had thought of it, but ALL the credit goes to Sasho78.
Thanks a lot!
Edited by dansidi - Oct. 11, 2016 04:54:31
Technical Discussion » per-particle attributes from Maya nParticles to Houdini via Alembic
- dansidi
- 59 posts
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Right, so I have tried some attribute wrangling, but I have very little experience doing this in Houdini.
I need to access data from the rgb_PP attribute array, in groups of three, for each particle.
This is creating three float attributes (red, green and blue) and a vector attribute Cd from the three floats.
When this is run, all the float attributes have 0.0 assigned to them, but I do not understand why.
Clearly, I am not accessing the rgb_PP attribute array correctly.
Can anyone help me with this?
I am attaching my little Houdini script and the alembic file I have been testing, which has a couple of hundred particles.
Many thanks
Dan
I need to access data from the rgb_PP attribute array, in groups of three, for each particle.
i@index = 3 * @ptnum; f@red = f[]@rgb_PP[@index]; f@green = f[]@rgb_PP[@index + 1]; f@blue = f[]@rgb_PP[@index + 2]; v@Cd = set(@red, @green, @blue);
This is creating three float attributes (red, green and blue) and a vector attribute Cd from the three floats.
When this is run, all the float attributes have 0.0 assigned to them, but I do not understand why.
Clearly, I am not accessing the rgb_PP attribute array correctly.
Can anyone help me with this?
I am attaching my little Houdini script and the alembic file I have been testing, which has a couple of hundred particles.
Many thanks
Dan
Edited by dansidi - Oct. 11, 2016 03:12:10
Technical Discussion » per-particle attributes from Maya nParticles to Houdini via Alembic
- dansidi
- 59 posts
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Hello again,
I have been given a clue to solving this problem, which is to use the Attribute Promote node, which will move the rgbPP attribute from the primitive, to the particle context.
Now, I'm not entirely convinced this is correct, but let's go along with it. Here is what happens:
Maybe you can see what is going on.
I have applied the attribute promote node to the alembic file, now I get a massive array of Cd on each particle. In the spreadsheet, the Cd columns go on and on until n = 3 * number of particles.
I have been given a clue to solving this problem, which is to use the Attribute Promote node, which will move the rgbPP attribute from the primitive, to the particle context.
Now, I'm not entirely convinced this is correct, but let's go along with it. Here is what happens:
Maybe you can see what is going on.
I have applied the attribute promote node to the alembic file, now I get a massive array of Cd on each particle. In the spreadsheet, the Cd columns go on and on until n = 3 * number of particles.
Technical Discussion » per-particle attributes from Maya nParticles to Houdini via Alembic
- dansidi
- 59 posts
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Hi All,
I'm sure this question must be a common one but I have searched this forum without finding the solution I need. So, apologies if I am repeating a previous post.
Right. What I am trying to do it take some nParticles from Maya over to Houdini for rendering in Mantra.
I am using Alembic to transfer the particles. Houdini finds the particle position, P, velocity, v, and particle ID, but not other per-particle data, such as rgbPP, lifespanPP, aimDirectionPP, etc, which I would like to carry across.
I can see that some data is there in the alembic file, but Houdini does not seem to be translating it properly.
Maybe you can see from the screen grab what is happening.
rgbPP, for example, is coming in as a massive array of floats, the size of the array is three times the number of particles.
I assume I need to wrangle the Alembic data in some way. I would be very grateful for some help with this.
I am fairly new to Houdini, VEX is not something I am experienced with, except for the very basics.
Maya 2016
Houdini 15.0.244
Windows 7x64
Many thanks,
Dan
I'm sure this question must be a common one but I have searched this forum without finding the solution I need. So, apologies if I am repeating a previous post.
Right. What I am trying to do it take some nParticles from Maya over to Houdini for rendering in Mantra.
I am using Alembic to transfer the particles. Houdini finds the particle position, P, velocity, v, and particle ID, but not other per-particle data, such as rgbPP, lifespanPP, aimDirectionPP, etc, which I would like to carry across.
I can see that some data is there in the alembic file, but Houdini does not seem to be translating it properly.
Maybe you can see from the screen grab what is happening.
rgbPP, for example, is coming in as a massive array of floats, the size of the array is three times the number of particles.
I assume I need to wrangle the Alembic data in some way. I would be very grateful for some help with this.
I am fairly new to Houdini, VEX is not something I am experienced with, except for the very basics.
Maya 2016
Houdini 15.0.244
Windows 7x64
Many thanks,
Dan
Edited by dansidi - Oct. 11, 2016 02:51:48
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