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Found 13 results

  1. 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.
  2. 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
  3. 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
  4. Pyro Jet Exhaust

    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
  5. 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!!
  6. 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
  7. 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?
  8. 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!
  9. just for curiosity stuff the navier stoke is coded inside Gas project Non Divergent nodes?
  10. 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
  11. 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 --------------------------------
  12. Gas Upres Retime Shaping Issue

    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).
  13. moving gas sim

    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.