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Found 158 results

  1. 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).
  2. Hi, Thank you for this forum.I need a little help from you guys.I am advecting particles by volume of smoke.I animated the scale source volume in the source density to detach smoke from the source and disperse the remaining one.Kind of a gradual fade out effect.How can I have particles disappear the same way?Currently they keep going.Any way to map the data of scalar volume to say alpha of the particles? Or is there any other way? Thank you.
  3. Hi, I am having some problem creating sharp and thin smoke using wispy smoke.I am a new user and not very proficient at Houdini but I have been trying on my own, gathering information from the forum. In a nutshell, I am trying the effect of a woman emitting smoke from her body.For this I shot the model on green screen, extracted the key and used the trace and scatter sop in Houdini.I have set my simulation.Since I wanted fine smoke, with more details, sharpness and crispness, I searched for the 'how to' get that and came across the 'ink effect' technique using millions of particles. I advected my particles with simulation, however, I think I am missing something.It is not retaining the shape of my sim.My idea is to use the technique to add finer details. Could you kindly take a look at my hipnc file and tell me what am I doing wrong?Is it that smoke is too thick with too many scattered points or am I doing something wrong in the particle network?Or may be there is a way to achieve what I want without getting into particles? I have intentionally reduced the number of particles temporarily. * Also is there any way to control opacity of particles with the sim density? The files below include the hipnc file, a few frames of alpha keys to be loaded into the trace sops, and a few frames of advection test render.This for some reason didn't let me attach the zip file so I am using dropbox. https://dl.dropboxusercontent.com/u/42878955/wispysmoke_advection.zip Thank you for your help.
  4. Hello everyone, I have some serious problems with the simulation time of my Smoke. Suddenly, from frame 69 to frame 70 the SDF calculation for the density source is taking for ever. But there are no major changes in the source geometry. The normal SDF calculation time ranges between several seconds but starting at frame 70 it takes 20min plus. (The source is the geometry from a fractured bulding) Where sould i start to look for a solution? Thank you in advance, Lukas
  5. steering large billowy smoke

    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
  6. Hi, I have set up a pyro dynamic that is driven by a some particles that swirls on a geometry box. I would really appreciate if someone can take a look at it and tell me what I can do to improve this. Its a system that lets the particles grow on a painted surface and the idea for me is to adapt this to other geometry later. Then I need to make the smoke and fire to look as realistic as it could be. I have also noticed that the flames are a bit not sharp / blurry in a way when doing a couple of frames in the render view. Im very new to Houdini so please explain to me a way that a newie can understand, I dont have a coding background, but use a lot of time to try to understand Houdini. Thanks. Stig pyro_test_SO.hipnc
  7. I have a smoke sim. I want to reduce velocity in the area inside of small box (like in pic). I want to have opportunity to fill this area with custom velocity. Thanks.
  8. Hey everyone! So I've been working on this tornado sim for quite some time. I have the particles doing what I want them to, but adding the smoke sim has given me a ton of trouble. I've gotten the particles to emit the smoke, but I can't get the smoke to follow the particle path, it just creates a ton and becomes a horizontal effect as opposed to a vertical tornado 0_o. What I think it comes down to is, how do drive the smoke with the velocity and direction of the particles to keep it from sprawling out all over the place and staying contained in the walls of the tornado? If anyone could take a look at my scene and help me out I would greatly appreciate it:) Brandon Tornado_WIP_V4.hip
  9. 2014's resolutions

    How are your New Year's Resolutions coming along? I think that in the upcoming year quit a few things will be come more obvious, clearer but just not quite yet ;-) '2014 The year where things become clearer'
  10. Hello, I am currently trying to render a scene from an intro to fx tutorial of a character dissolving into smoke from points being emitted. In the scen viewport I have a color ramp on the points and it renders as a colored blobs. I am having trouble assigning a smoke shader. What is the best way to render smoke from points? Thanks
  11. Ok so here is my dilemma (one of many lately i know... Im very new to Houdini so please bare with me) I am trying to emit smoke from particles but as you can see from my video attachment, it looks as though the smoke is only emitting mostly from SOME particles and not the others, almost like smoke is choosing which particles to emit from and which ones not too. Also the smoke is going to mostly one side instead of equally spreading out. Maybe i forgot to do a step, but from all the tutorials ive watched i feel ive done every step. I feel very stuck I also am posting some pictures of my Location POP settings. As always, any help is greatly appreciated! ParticlesTest_1.mov
  12. Useful Pass for Particle effects

    Hi everyone! Am working right now on a shot. It's a sort of ink effect with a mix of millions of particles and wispy smoke. Am pretty PEON to particle rendering and I was wondering if anyone could tell me what are the most useful pass for particle effects. For the moment, the pass I will use are: -Beauty (constant shader) -Depth of field (grayscale) Technique based on this thread -----> http://forums.odforc... field__st__12 -Age (grayscale) -Shadows (still searching a good way to fake shadows) -RGB(3 lights) What is the best way to use this pass? Do I have to use those three channels separatly as a Mask? What are the most useful pass for particle rendering? Thanks ODFORCE.
  13. Hi everyone I need some urgent help with an effect I am trying to creat. As I already stated in a different topic, I am quite new to Houdini. To my problem. I want to assign color to my smoke. So far so good. One might think as simple as using point color on billowy smoke should do (after all thats what it is supposed to do) - but turns out it is not as simple as that. So I have found a couple of forum entries regarding how to assign color to smoke. The most interesting sollution was by David Lin (Emit smoke from texture) - I noticed it also used the same way of transfering color to the AutoDop and Import Smoke DOP. However neither of my setups seem to work. I will attach my files here. There are two setups: 1.SmokeColor-Issue ...using a setup assigning 2 plain constant colors as point attributes 2.SmokeTexColor-Issue ...trying to use a texture to assigne the colors to the setup (also required files - texture, and a geometry file) In the first case the resulting smoke is simply black. Or results in false colors. In the second setup the resulting colors from the calculation to transfer the texture color result in plain false colors! I suspect my calculation is wrong. So in all there are two problems I have spent days on to find a sollution but could not fix it: 1. Smoke resolving in wrong colors 2. Texture color Transfer issue Hope someone can help me here! This issue has been driving me crazy for the last week! thanks! PS: don't concern yourself with the slightly overcomplicated setup of some things - Its a dirty workaround for the Import scale Issue derived from Maya..... unless that would cause all the problems? Smoke_Color_Issue.rar
  14. hi i want to render smoke with the matte of debri inside smoke to give a depth of atmosphere.
  15. Hi, I'm new to volumes and smoke sims, so please excuse the basic question here. I'm trying to imitate the look in the image linked below http://greatlakesecho.org/wp-content/uploads/2011/07/Mercury-ucsandiego.jpg I want to get big billowy smoke coming out of the smoke stack and have the smoke spread out. But what I am getting in my sim is the smoke condensing in the middle like a triangle and then going up. I've tried playing around with bouyancy, adding initial velocity and finally adding a uniform velocity in the autodop network. Are any of these solutions going to give me that look? I'm learning mainly from tutorials online, like peter quint's vimeo tutorials. Is there a better source for learning material on smoke (that is up to date ;-)? thanks in advance! James smoke_stack_v07.hipnc
  16. pyro shading techniques

    I'm looking into achieving more realistic looking fire and smoke renderings from pyro. I'm primarily looking into rendering explosions and other pyro effects that combine an emissive source like fire with dense smoke. I've been looking at a couple demos people have done online such as this one: https://vimeo.com/62118350 The shading in this video is what I'm after. I've been playing with the pyro materials packaged with houdini as a reference (the fireball material). Do you guys render your fire and smoke in one go? or separate those elements and assemble in comp? I'm trying to get good looking explosions that scatter illumination from the fire onto the smoke. And getting fire in explosions to feel better integrated. Any tips or tricks for shading would be greatly appreciated.
  17. Hi, I finished a smoke sim and now I am looking to render it. I am using a Pyro shader and I transferred attributes from my pyro object in DOPs to my shader. However, I am getting very different results in the render - its not looking anything like the visualization. I am using micropolygon with depth map shadows on the light. Any ideas on how to fix it? Please see attached screenshots and file. Thanks. od_Smoke_Render.hip
  18. Multple Custom DOP smoke domains

    I have a few dozen smoke simulations that I want to run in a single DOP. They have separate domains, and I'm trying to find a way to have a single Smoke DOP generate N smoke containers, and assign each container to a seperate domain bbox. I eventually want to assign custom division sizes to them as well. Extra credit for being able to assign non-axis aligned domains.
  19. Dear Houdini Community, I've been trying to figure parameters of curl noise for my parameters and I've been stuck for quite a while... My object moves fast from left to right and emits particles behind. I used curl noise to create curls, but I can't make the curls bigger. They should quickly fly out of the object and then curl and disperse in the air. I am attaching my sketch which is easier to understand. Any hint appreciated. Have a nice weekend :} ~ashe bigger curl noise.tar.gz
  20. multiply collision with density

    Hi everyone I'm using a smoke simulation where a simple source is dripping smoke on a collision box. The collision uses the sourcevolume method, so I have the SDF collision available. I'd like to create an additional field which is nothing else than the result between the multiplication (intersection) between the collision field (after gassdftofog) and the density field. Basically I'd like to use this resulting field into a pyro symulation (a separated sim) as fuel to emit fire. The result would be that some fire emits from the locations of the cube where the smoke is dripping. I used a match field to fill a field "collisioncopy" scalar field, and filling it with the content of the collision sdf after converting it to fog. Then I used a gaslinearcombination with the folliwing calculation collisioncopy=collisioncopy*density The problem i have is that obviously the collision field and the density field are mutually excusive so the result is an empty field. My question is: is there some quick and dirty way to "expand" a certain field by a certain amount of voxels (in the direction of the gradient of its density for instance). This way i would be able to have an overlapping area between my collision field and the density and I could calculate the intersection between them.
  21. Hi guys, I'm working on a project where I have to generate smoke like effect to define a character's movement. So taking alembic export of the animation, and converting the mesh to particle interaction within the boundary of the mesh. I'm doing some test with simple sphere where particle interaction happens inside a moving sphere. I got some problem where after birthing all the particle inside POP net, it doesn't follow the translation (or rather deformation) of the mesh. What I wanted is generally represented with particle sop where the particle are birthing and interacting within the sphere even when the sphere is moving around. I just need to get the same behavior inside pop net. Does anyone know what I'm missing? I tried using collision inside pop but that means interaction within the surface of the mesh and not really what I wanted, Ed particleTest.hipnc ballTest.abc.tar.gz
  22. Hello guys! This is a FX breakdown for a school project. The goal of the project was to create a World War 1 scene. The total length for the shot is 35 seconds. It is worth to mention that this is mine and Davids "Skybar" second project using Houdini. We wanted to learn the Maya-> Houdini pipeline and we used alembic to achieve our results. Houdini was used for all simulations. The artilley hit and a great part of the explosion shading was made by David. I was responssible for the tank explosion, tank shot and the tank's exhaustion pipe smoke. We had one month to learn, create and render all the simulations as well as doing some rotoscoping and modelling. We were able to do all of this with your help, with this fantastic forum with lots of information and knowledge. Expect an update with higher smoke resolution and less flickering on the glow from the tank explosion. I hope you enjoy it and have have a good one! /Hudson & David
  23. Hello all! My work occasionally uses Houdini, so I've been trying really hard to learn the ins and outs this past year. I have a scene, here, that contains a large and fairly detailed smoke simulation. It starts out rendering quickly enough, but soon slows to the speed of a frozen snail glued to the bottom of a large brick. I've looked at several posts here and elsewhere on rendering smoke, and I have a general idea of what could be taking so long, I guess, but I thought it'd be wise to post my scene file and ask a kind soul to glance at it. Is it just the size and detail of the simulation that slows it so much? Some render setting? Both, equally? :shrug: The only difference between what I was rendering and the version I'm posting is the inputs and outputs (cache, render, etc) are deleted, and I also deleted what little geometry it had. The emitter is in a strange place because the camera move (deleted from the version I posted) and geometry were imported from another application. My computer is very fast, but if I should be more specific in that area just let me know. Thanks very much in advance. Grey smoke.hipnc.hip
  24. Hello everyone! I have a question about local transformations when emitting smoke in H12.5. I created a cylinder oriented on Z axis, I rotated it 45 degrees around Y and I made it emit smoke. I wanted it to emit the smoke in the direction of its local X axis, so I added velocity along X, visualize the streamers (the streamers's direction looks perfectly OK) and run the sim... The outcome is on the picture: As you can see, houdini ignored the local axis of the object and emits the velocity in the WORLD X axis.... The same thing happens when I use the empty geometry and object merge with transform set "into this object" and then make it a smoke source... Can anyone tell me what am I missing? I can't find any simple way to tackle this... I have a workaround involving reading the normal of one polygon and then, using attribute transfer I feed the N channel to V and it is working, but it's COMPLICATED, I cannot believe there isn't any other (simple) way to emit smoke with velocity in the direction of emittor's local axis... Any help MUCH appretiated!
  25. Dust - various doubts

    Hey everyone, It turns out that Im working on a dust simulation from fractured rigid bodies. This simulation has 1.4 Divisions and before I enhance the Divisions to cache again the final sequence, I want to fix this problems Im having. Im using Whispy smoke shader. In the light blue square, the smoke seems to have dots inside, like a net. Why is this happening? In the red circle, there is a pretty flat end of the dust, how can I make this simulation more like a ball while the tip goes down? Im ok with the yellow circle, I like to see the rigid bodies through the dust, even though how can I set more density in the smoke so that the early smoke lose density and the new one has a lot of it? Trai