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Hello everyone, I'm working on a very specific earth/ground blast. Inorder to keep the max control I decided to create pre sim wich would be used as a source for the main simulation later. Or I'm going to build it in directly and blend it with a pyro solver over time. Anyways, the goal of my setup is to create blast trails wich have an outward momentum. But having a vel field wich pushes density outward causes mushroom with a pyro solver because of the nature of divergence correction. A custom solution should help me out but I'm stuck cause the vel field is not expending but keeps clipping to the density source region. Even vel is advecting vel. There is already a post which seem to had a simular issue but it didn't work for me. advecting velocity by itself. Any ideas? vel_clipping_issue.hip
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Hi, By default, heightfield erode node is only applicable on heighfield data. I'm wondering if its possible to use it on a regular polygon mesh? I want to use a heavily modified mesh (i.e. logo, hero asset) and erode it. -
Hey folks, proud to present LYNX Tools, a collection of production proven open source tools to accelerate your workflows! All mentioned tools are free to download via the links below and are licensed with a full HoudiniFX license. All Houdini Assets have complete Houdini native documentation available. Repository: https://github.com/LucaScheller/VFX-LYNX Lastest stable release: https://github.com/LucaScheller/VFX-LYNX/releases Please give them a test drive, so we can improve them further Roadmap | https://github.com/LucaScheller/VFX-LYNX/projects/1 So far there are three tools: LYNX_force_general | Tweak your sims with this all purpose & intuitive force field. Built to mimic force fields in other DCC applications, but with support for more features and a natural Houdini user experience. https://www.lucascheller.de/vfx/2019/03/24/vfx-lynx-houdini-force-general-asset/ LYNX_fabric | Create fabric/weave patterns with ease. Perfect for creating that holiday sweater you never wanted. https://www.lucascheller.de/vfx/2019/03/16/vfx-lynx-houdini-fabric-asset/ LYNX_velocity | Get control of your velocities via an intuitive UI or groom them for absolute fine tuned control. https://www.lucascheller.de/vfx/2018/11/01/vfx-lynx-houdini-velocity-asset/ More info on my website, including full release logs: https://www.lucascheller.de/blog/ Houdini User Group Munich Presentation: https://vimeo.com/334887452
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Hey guys, What is the best way to use the slip on collision control field, to avoid viscous fluid of sticking on objects? I managed to do it with the help of a friend, using the gas match field + a source volume. it works fine for static objects but not at all for moving ones. I have a project with an alembic animation and I really need to use it on the animated surface. Can someone help me? Here's the setup in dops: Here's it working fine with a static object. It's a top view and the red box is the sliping object: and here the red box is animated, not working: Not sure if this is the best way to approach it so any other ideas would reeaally help me scene file is attached Cheers, Alvaro flip.slip.v2a.hiplc
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Hi, I love the "wind tunnel direction" feature in the sparse solver, and I would like to find a way to mask it's effect. I know this is just a vector field node with "External Direction" set to a given value, but I don't know how to apply a mask to it (say I'm simulating a chimney with smoke rising out from the top. I wouldn't want the wind inside my chimney). I can do this inside the gas wind node or with any other force node. The problem is: none of them look nearly as good as the "External Direction" option in the vector field node! (with gas wind being the worst). I've tried using the "Sop Vector Field" node, and plugging in a sop field with the same value to what an "External Direction" value might be. It kinda works, but not quite. The result is not the same, and I noticed that the velocity field is getting incorrectly updated. (it flashes in and out of active areas when "activated") - also it's slower I hope there is a Gas DOP expert who can help me. Basically what I want, is a wind that looks as natural as the "Wind Tunnel / External Direction" but with the ability for applying masking (and other stuff if possible). Thank you so much, if you actually read this. Thank you even more, if you can help Best Regards, Asger Mortensen.
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Hey guys, how can I create a custom field on FLIP? I'm trying to achieve this. I guess I could advect the new field using a gas advect but I just can't add this new filed to the sim. Scene file is attached with a small progress Thx Custom_Field_Advection_0101.hiplc
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Hello guys ! It has been now 3 years I'm working in the VFX industry. I saw a lot of different FX artist/TD so far and I came to the point that there is many ways of doing a pyro sims as there is artist to make it... From all those different artist, I met people doing amazing simulation from really complicated pyro solver and other with a only a few nodes. There is one specific topic I wanted to get thoughts from you guys was the using of the speed field from the length of the vel field versus the pressure field. People tends to use one or the other as a mask for turbulence, disturbance etc.. in their pyro. Both seems working farely well, but I would like to know more about the prons and cons of those technics ! Looking forward to read your thoughts ! Cheeers
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solved. thx
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Hi I'm new to Houdini and recently I've been getting into DOPs. I have a question I've been trying different things out in dops to see how they work, been playing around with the "Gas Match Field" node and found that it works quite nicely when both fields you are supplying the node with are from the same object Like on picture 1, both the "myField" field and the "heat" field are part of the same object and the node works just fine But what I can't figure out is how to make the node work when I'm supplying it with fields from different objects. On picture 2 "myField" is part of an empty object and the "heat" field is part of the smoke object, I tried to reference them via their paths like on the picture 2 but unfortunately it doesn't seem to work. Does anyone have any insight into why this may be, I can see how referencing field from different objects can come in handy not just for this scenario.
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Hey! I'm looking into a way of keeping my volume inside the vortex boundaries, at the moment when it spins it goes out, any idea? I was thinking about a torus shape volume around it with custom velocities to push it inside when it goes out, but maybe there are better solutions! cheers!
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Hi, Lets say I create a box node than iso offset and set the name to density. I have a volume with density. What if I want to add a temperature field? I know I can duplicate the iso offset, change the name to temperature, then merge the two volumes. Isn't there a better to add other fields? Perhaps using name sop or VDB node? Thanks
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Hey, I have a sim of a roof being exploded. The tube you see is providing velocity to push the chunks outward. I am using a field force and I am using velocity from my tube as the force attribute. For some reason, the field force only affects small chunks, as outlined in the photo. If I go to my packed object (the roof) I can change the density from 1000 to like 1, then finally all chunks are affected. That creates another problem because the smaller pieces move like 20x faster than the larger chunks. I suppose I could use @speedmax or a pop speed limit. My main concern why does the density affect field forces velocity being added? Why is it soooo extreme (because the smaller chunks are not that much smaller). I tried treat as wind in my field force, but that does not help either. Is there a better way of doing what I am trying to accomplish? Thanks
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Hello, now when I am loading VDB volumes with File SOP it sometime takes some time, especially with big volumes stored on network. I was wondering whether it is possible to load only specified volumes from a VDB file, for example to load only heat, to keep loading times slower. This would save a lot of time in situations where I am blasting all other volumes which I do not need directly after File node. I quickly checked docs and found that it is possible to firstly read the header to find out information about stored VDBs and then to load needed volume (in Reading and modifying a grid section). Any ideas if it is supported right now in Houdini implementation / or if there are any plans to add this? Juraj
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Hello everyone, I've been getting into DOPs recently and i just cant figure out something. I have a SmokeObject and an RBD object. They are both plugged into the Pyro solver. The smoke has a collision relationship with the RBD object, and the Pyro solver's option "Temperature Merge" is set to "Collision Interior". In order for the "Temperature Merge" to happen the RBD object has to have a temperature field. Now what i want is for the RBD object's temperature field is to be just like what the smoke's temperature is but subtracted by a number so that the RBD object is always cooling the smoke. I've Created a fog volume that consists only of value 1 voxels inside the RBD Object and value 0 voxels outside of the RBD Object. I'm planning on using this as a mask for the smoke's temperature field (multiplying these two fields) and then lowering the value for all the kept voxels. Now i don't know what is the best way of achieving this but i thought that I can bring in the mask field (the only 1 or 0 field) into the dop network using the "Sop Scalar Field Node" and then extract the temperature field out of the SmokeObject using the "Fetch Data Node", wiring these two into the "Gas Calculate Node" and then blending and doing post subtraction in there. I don't even know if that is the right way to do it, but anyway once I connect the scalar field (the temperature mask, brought in from sops) into the gas node everything is ok. Once i plug in the data (SmokeObject's temperature field) into the gas node it reports an error saying that the connection to the fetchdata node is the wrong type. How could this be? Both the "SopScalarField" and the "FetchData" nodes output data, how come that the gas calculate will accept data coming from the "SopScalarField" node and not from the "FetchData" node ? I've been trying to resolve this for a while now, if anyone could help out it would be greatly appreciated
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Hey guys recently I saw that rest field inside pyro solver, that I read at Stalingrad Article to create flames in SideFX site, but I dont have any idea how to use that , anyone have a document/explanation for this? Thanks
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Hi everyone. Does anybody know how to use surface field in voppop or some dopvop to find the distance between my particles and surface. I want to make a force wind that depends on distance between surface and particles, so the farther point from the surface, the stronger the force of the wind. And the surface has really big waves for example, thats why i cant use just P.y for power of force for flat surface. Hope I explained it clearly)
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Hey, I'm curious about different approach for artistically control the creation of a velocity field. I've learn how to make nice noisy, curly etc.. fields, but when it comes to controlling them more, how would one proceed ? could some curves be used as general guides for the velocities? And the perturbed slightly by some noise ? I bet there's many ways to do it, I've seen some nice VolumeVOP work in some tut (volume trails), but I wondering about the best way to get real control. thanks in advance for any input
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Hi, first of all sorry if this has already been asked. I'm advecting some particles from a pyro sim. I would like to transfer some attributes from the pyro sim to the pop sim, like density, color, other... I have to use the gasfieldtoparticle node if I'm correct, but I cannot set it up correctly. Here is my DOP network I don't really know the correct way to use this node, could you please enlighten me ? [another question out of topic, do you use win10 on a work machine and do you recommend it?] thanks a lot!
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Hello there, i'm stuck in a particle simulation, here is my issue : I have an animated bird geometry that goes through a cloud of particles, and I want his wings to create wind and swirls. I managed to compute velocity with a trail node... but i can't find a way to have a vector field simulation out of it. Can anyone help me ? (it may be a stupid question... but i'm new with houdini and i'm a bit lost between the different tools)
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Hi, I have a keyed gravity that affects a FLIP simulation (a box of water..), and I am trying to find how I can offset my gravity force to start with top particles down to bottom. Ideally I would have an animated box that would trigger the gravity effects on the particles... After a lot of research, it seems that I need to use the mask slot of the gravity but can't figure out more than that, as I don't see in the viewport any feedback for the scalar field and vector field. Help? Thank you!!!
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Hey guys, I have a large billowing smoke sim a wall of smoke from different sources. I need to steer the volume, like have it turn at a certain point. What is the best approach to steering or having thick volumes follow a vector. Right now I've tried guiding the smoke using pumps by making some geo that acts as a wall with custom velocity vectors to push to smoke around. It sort of works but the smoke expands a bit too much and doesn't really seem like its being directed, also seems to lose it's volume. any tips would be appreciated
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Hi all, I am having some weird artifacts in the velocity field generated by a simple FLIP simulation in Houdini 12.1. Basically the more I reduce the particle separation of the source fluid object to get a higher res, the more I get peaks (1-2 frames max) in the velocity field, popping here and there in the fluid. It happens mainly on the bottom of the fluid, and that is easy to get rid of. The problem is that it happens even in other parts of the fluid when some object collides and interacts with the fluid. Now this would usually not bother me cause what happens underwater is rarely visible, but in this case I am implementing a white water generator and those velocity peaks are creating unwanted annoying water foam underwater. I attached a scene file that shows the issue. Did anyone experience the same issue and solved it somehow ? water_tank_h12.1_05_odforce_test.hip
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Hi guys, I was playing with a sim, importing a vel field from a bgeo cached file and merging it with a cloth simulation, so the cloths reacts to the vel imported. Also the cloth has his gravity. All the networks works well, but then I tried to put a wind force, to move the cloth a little more, taking the vel not just from the imported field, it seems that the wind force overwrite completely the imported vel. I've tried to modify the force without any change. Than I've deleted the wind force and added a uniform force with a noise field and all worked fine. Why's happening?
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Hello, I am playing around with the VDB stuff lately and most of it works great. But I noticed that i can't use a plain VDB node and create based on the dimension source a volume, like a velocity field. It always said "<empty>". I like to create a vector field and then manipulate it by the Volume Vop as with the standard Houdini Volumes. Any tips or a workflow explanation would be great. Thanks nap vdb_empty.hipnc.hip
