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Showing results for tags 'gas'.
Found 25 results
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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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Hello, I am trying to work with OpenCL but as soon I enable them on few nodes, like the gas disturb, gas turbulence, it stops working. I just get a mushroom smoke effect. Does openCL not work on these fields? I have attached some screenshots. The first image is without OpenCL, the second one is with smoke disturb disabled and the third image is with openCL enabled on Smoke disturb.
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Hey all I have some low-ish resolution VDB dust clouds created in C4D with the TurbulenceFD plugin. These contain velocity channels. So far, I'm just not satisfied with the overall detail. What I've done to try and increase detail is convert the VDBs to Volumes, Volume Resample them, then use Volume Velocity to add some curl noise. It's looks OK, but by no means what you would call a true Up-res, that uses existing velocity channels to increase detail in turbulent areas... So that's the question really. How do I take a pre-calculated VDB (not dynamic at all) and give it a high-res makeover? Any pointers would be appreciated. Please be aware that the overall motion has been signed off, so all that I should be changing at this point is detail. I would just do the Up-res in TurbulenceFD, but it's buggy as hell and wont work. Every day I get closer to ditching C4D entirely. Thanks!
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Hello, I am really confused with Gas Disturb node. I tried reading the documentation and tried different values but I haven't seen much difference when I change the Threshold Range value. Can some please help me and explain what exactly the Threshold Range is doing? Thanks.
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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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Greetings, I have few microsolvers in my Flip Solver>Volume Velocity and I want to apply them to only 1 of my 2 emitters. Do I use a POP Wrangle after my MicroSolvers like (if viscosity > 500 then apply) or do i need to make some initial groups of my particles and apply the micro solvers to the favoured group ? To be more specific I use a GasMatchField and a GasStrainIntegrate with a GasStrainForce and I have 2 Volume Sources. If for example I go to my Popdrag in Groups I can see the option "stream_volumesource1" or "stream_volumesource2" but nothing like that in the microsolvers.
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Hi, I'm trying to use a pyro sim to make some realistic clouds and to get the effect I want I need varying levels of dissipation, turbulence, and disturbance at different heights. I've set up some scalar fields and made a gas wrangle to have the gradients I want set up but I can't manage to get them to properly affect the gas nodes. CloudSimming.hip -
Hey! I'm trying to get a very low freq turbulence in my smoke trail sim, but even if I put pulse length to a very high number, 10000, the turbulence keeps moving with time, while I want some sort of static turbulence to break my trail line..any idea? cheers
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Hi everyone, I am trying to set the values to a collision field in a gas wrangle. I am using the gas build collision mask node to create the necessary fields and then I am trying to set values with a gas wrangle. Is it even possible to do it this way? I have a example scene that shows how I set it up now, that doesn't work. My purpose for this that I want to be able to simulate a 2d smoke simulation and collide to an object on a different height for every voxel. I will eventually want a separate height field that will accumulate the density and this heightfield will be the Y position for the voxel to check the collision. I am quite new to smoke/pyro simulations, so this scene probably doesn't make any sense gas_collsion.hipnc
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Hi Guys, I am struggling to achieve a believable blood in water effect. I was hoping someone could give me some tips or advise to help steer me in the right direction. Currently I am using a pretty simple pyro setup and sourcing a custom vel field, in an attempt to simulate underwater turbulence. I am also wondering if I may be approaching the problem in the wrong way and if there is a better solution. I've attached a scene file incase this helps. I have posted an example below of the look I am trying to achieve. Between 0:21 and 0:25. Essentially the blood flowing from the chunder and dispersing. Many thanks, Clive Blood_in_water.hip
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smoke Basic smoke moves through collision geometry
cybor09 posted a topic in General Houdini Questions
Hi people! I'm learning some things in Houdini to create HDA's for cinema 4d or export vdb's simulations to render in c4d. In this case, I want to make a smoke simulation but I have one basic issue that I'm sure it solves with a simple way. I have one torus emitter inside of a tube but the smoke doesn't respect the tube geometry, It moves through it. How can I fix it? Thanks!!
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Hi again, I have an explosion being sourced by particles. I have a gas dissipate micro solver to make the fuel dissipate faster because too much fuel is lingering after the explosion. However, I also have another source of fuel which is for the fire that keeps burning after the explosion has ended. My problem is that I only want the fuel from my particles to dissipate and not my fire fuel. Can I somehow limit the gas dissipation to only affect one of my fuel sources while my other fuel source remains untouched? Thanks in advance! Edit: Should the fire be a separate pyro solver? If so, how can two pyro solver affect eachother?
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Hi, In my pyro sim, I just want to add some velocity in the container before my smoke begins emitting. I could do this by creating a box and using fluid source and adding curl noise. I did not really like the results, so I decided to try something else. I tried adding a gas turbulence and turned on the velocity visualizer. However, gas turbulence doesn't seem to affect the container until density enters the container. I tried gas disturbance. Disturbance did add velocity to the container, but I noticed the field set to disturb was "temperature". I changed the field to disturb to velocity and it stopped working. Why does the temp field work but not velocity? Why doesn't the gas turbulence not add velocity until density enter the simulation? Thanks
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Hi Guys, I am currently working on a shot where I need to simulate an object falling slowly through deep water whilst bleeding (The more blood the better). Initially I began with a pretty simple setup, An emissive object, a collision object and a divergence volume which is being used for expansion. The problem I am running into is that I need the smoke to continually expand, whilst becoming more diffused and transparent, but to always remain in the sim. So I have disabled dissipation as I don't want to lose density, but this leaves me with a dense volume which isn't transparent or diffused. I would like the density that is in the sim to have an aged based blurring. I did try to achieve this with a gas dissipate and heat field but this still wasn't right. I have also spent time trying to tweak the pyro shader to achieve the desired effect but I am not having much luck. Below is an example of the look I am trying to achieve. Between 0:21 and 0:34 Any advice will be greatly appreciated. Many thanks, Clive Blood_in_water_odforce.hip
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- density
- transparency
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Please, I just need a couple of pointers I've been trying to set-up a pyro simulation, have some smoke rise up and collide with an rbdobject. I've uploaded my hip file and written all my questions and problem explanations in there. Plus I think that it's much easier to understand if you have my hip file instead of me trying to explain it here in text form. Please take a look at it. The gist of it is : The smoke has a temperature field. And I've wanted to lower the temperature field of the smoke that comes in contact with the geometry so I've come up with the idea to give the geometry it's own temperature field and tick the temperature merge option on the pyro solver. In order to create the geometries temperature field I plan to make a volume mask to mask out the smoke's temperature field so that i'm only working with the voxels that make up the geometry and then lower their values, the result will then be the geometries temperature field. I've listed all the problems and explanations inside the hip file please take a look Any suggestion is greatly appreciated Thank you Houdini_DOPs_pls_help.rar
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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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Hi guys ! I'm trying to make a afterburner, jet gas exhaust effects, but I'm struggling right now. I looked at the Pyro Jet Exhaust HDA from SideFX (https://www.orbolt.com/asset/SideFX::pyrojetexhaust). I opened it and look how it works but I still can't understand. There is no combustion, no flames, no smoke, is it just fuel/gas ? If this so, how can I make it collide with an object ? Like when a rocket beginning to launch, the afterburner collide with the floor. Thank you for your help guys
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Hi Guys, I have recently started experimenting with Houdini and have stumbled upon a problem I can't seem to find a solution to. I have a Pyro fx explosion setup and I would simply like the gas resize field to reach the maximum bounds of the container and then switch off. Currently, whilst the smoke is dying out, the resize container is scaling back down to the size of the emitter object resulting in a visible bounding box in the render. Any advice would be greatly appreciated, Thanks, Clive -
Hi Guys, I'd like to know a way to control different forces, based on some attributes. I find is very easy to control Pop Forces based on position or velocity or Cd attributes... but I want to have this control using for example Gas Turbulence or Gas Surface Tension to control my fluid... Imagine I have one liquid that is flowing along a curve and after TX > 5 it will increase surface tension and turbulence. How would you do that?
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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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just for curiosity stuff the navier stoke is coded inside Gas project Non Divergent nodes? -
I have been at this project for a while now and am so sick of this not working. I just can't seem to make the tornado spin around the right way and be more directed by the particle movement. Can someone tweak this and give it back or merely give some suggestions based on the file? That would be awesome! Description: Particles emitting from circle based on surfaces. Volume from Tube for velocity input. Made normals controller to direct toward center of tunnel and down. Emitting fluid from particles using pyro solver from the billowy smoke shelf tool. Thanks so much!! Tornado with fluid_fuel try3.hip
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Hey Everyone on this beautiful sunday! So, as I am touching pyro for the first time, of course I am using the "Gas Resize Fluid Dynamic" node (from here on out called the "resize node") in my DOP-net to auto adjust the grid size. However, I a getting this slight flicker in the simulation, as long as the container size is being modified by the resize node. As soon as the container has reached its maximum size, and no resizing is going on anymore, flickering stops. Turning off the resizing and letting the container have static dimensions, also eliminates the flicker of course. Anyone out there familiar with this? I tried messing around with the resize-node's "Subtract Threshold" parameter, since it seemed to me (from the help) this might be connected to the problem somehow? But no luck so far.... Thanks for having a look people. resizing active, flickering results before the gridsize comes to rest resize_flikr.avi resizing disabled, no flickering noresize_noflikr.avi --------------------------------
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I've added the gas upres node in a duplicate of my dopnet (smoke simulation only no combustion). I have exported the vel, density fields for the original sim. Then I animate the absolute frame in the upres node (starts at 1- 50F and then slows down). However the retimed sim looks similar but more smooth out, like a mushroom cloud instead of thick and thin layers blending together. I tired to introduce some turbulence from the upres node but it doesnt solve the problem. It's as if the sim became more thicker and blobby. My only solution right now is retiming from the original sim via timescale animation and counteranimating dissipation, turbulence when the smoke slows down. Any ideas how I can do a proper retime with the gasupres node (also look at how the shelf tools set up the network).
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I was experimenting with having a gas sim on a moving object. The emitter translated with the object and left a trail of mist. Since the emitter was moving, the voxels at the emitter always looked very crude and low rez, no matter how many substeps, and no matter the resolution. By the time the smoke got about 20 frames of dynamics, it started to get some detail and look good, but this was never the case at the emitter. I got much better results by just running the sim in world space (not animated) and blowing the sim back with a wind. Is there a way to specify that a gas simulation grid is actually moving with a given velocity? Or are all grids implicitly static? That way I could have the simulation grid parented to the object, but DOPs would know its moving in world space and do the appropriate dynamics.
