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Found 138 results

  1. Hello, I have a problem with a FLIP fluid scene. I fill a sphere and move it down and upwards. After this movement, I have the same amount of particles but not the same volume… By the way, are there any good practice collections for flip fluid? I'm still struggling with it. flip.hiplc
  2. VDB RENDERING ARNOLD

    Hey ! So I made a particle simulation in houdini, from a base mesh then I convert the particles to VDB and then back to polygon with the the convertVDB node. I exported a frame in OBJ en opened in Maya, next to my original base mesh. I apply the same arnold volume texture to both, and I got 2 totally different looks. How is this possible ? They are both polygons ? (The one in T-pose is the original base mesh).
  3. Heightfield Isolines?

    I'm meddling with Heightfields and one thing that seems to be missing int the workflow and amazed me in 3DSMax Forest plugin is the convert masks to curves. Is there a way to create isolines in Houdini from either @height or @mask? I'm looking into creating road/river/track networks into terrain so if there's any good reference to follow let me know, thanks. For now I'm just generating them irrespective of the heightfield.
  4. how can i do the detail up of smoke?

    hi guys i want to my smoke sim detail up. my data is too close so i want to use noise in second-half work. for example, in Shader or Volume Vop noise. i used do noise in Billowy Smoke but do not recognize rest field.( I have rest field) it looks like world noise. and i found this docaument while i was looking for it. (https://fxnomemo.blogspot.com/2015/07/volume-displacement.html) but i'm not sure how to use it in SOP(Cloud Noise, or Volume Vop) Can someone tell me?
  5. I have a dynamic volume that I want to render with redshift. It is not a pyro sim but when rendering the density changes as a function of time, so by about frame 100 it has dissapeared. I want it to stay the same. I cant find an attribute in the redshift volume shader related to time. Can anybody help me? I basically want the render to be the same on frame 1 as it is on frame 500. The volume is generated via a point cloud that is rasterized. THanks!
  6. Hi guys, I'm in trouble with the new Volume Source node. I can't import a simple VDB from SOP to DOP as a collision object, let me explain better. There is a Pig Head converted in VDB by Distance, it has got two attributes: surface and v. After creating a simple DOP Network, I've tried to import the VDB object by the new node Volume Source. I set the correct path, changed the source volume initialization from smoke to collision, changed the source volume paramter, turning its name from collision to surface (to import the attribute I got in the SOP pig head), but nothing appear in the scene view, it doesn't import nothing. I also tried to modify the field to match, setting surface as field to create, nothing happens again. I'm trying to solve it for a couple of hours but I'm still stuck. Can someone help this stupid beginner? Thank you in advance.
  7. Hi magicians, I was trying to create render passes for the fire, I want my temperature and fuel to be render as different render passes, I tried to use temperature and fuel as float in extra render images, but the problem is that, I am not been able to get it properly. what is the way to get render passes for temperature, fuel and heat in extra image details ? I would also like to know the way to render normal passes and any other passes which can be rendered out from volume, like opacity pass or something helpful in compositing. I get the fire mask from the shader but it is not that useful. Thank you.
  8. Layering Volumes, oddly subtracting

    Anyone might know why my volume is being subtracted, as I'm layering volumes together, saved as bgeos in separate geometries. when rendered it's oddly subtracting from one another in some areas.. like negative values affected it in some way. same approach as just set dressing a bunch of different clouds. // edit The houdini renderer I believe, reads negative values. And my odd manipulations have achieved this effect.
  9. How is it possible to convert a single volume, to 3 volumes (velocity) I have shaped form that I am converting to a volume. I then need to convert that volume to vel.x vel.y and vel.z, to create a velocity field of. it is not optimal to just create a bound and then convert it via a "Volume" node, because I need to keep the original shape.
  10. Hey guys, I have been having troubles with extracting transforms from an incoming alembic and apply it its vdb. My guess is, that you extract transforms using transform matrices in VOPs and apply it to the position of the vdb. But I don't know how. Can somebody help me with it please? -bf
  11. I'm emitting smoke with colors. After adding and creating dop fields import with density, vel and Cd channel for rendering the colors are not visible in the render. When I'm visualizing them as color channel everything works fine. How can I make volume colors visible in Redshift render?
  12. I have a main volume that I want to render. however In that volume I would love to be able to merge other volumes into it and use those volumes as extra image planes. This means that my second volume should NOT show up in my beauty pass, but be available as an AOV. is this possible? Right now I have it setup so I render the second volume separately, but I wonder if the other thing could be done?
  13. Subdivide / interpolate voxel?

    Hi guys, I'm working on some pyro simulations which require dense fluid look. I have to crush the density remapping to achieve the dense look. But the banding issue appears. So I'm thinking is it possible to subdivide each voxel to 8 small voxels and interpolate the density value? Thanks!
  14. "Foreword" - MULMO

    Hi guys, Here is a new MULMO piece of work, fx all done using Houdini, enjoy! ludo
  15. Hi guys. I am trying to utilize my point attribs in a volume. how can I: - set the volume color (shade the volume) using my point color? - when volume is created, get it to read already set density values on the points. (volume rasterize). attached is an example file. cheers colortovolume.hiplc
  16. Hi I've been playing around with the wdas data set cloud and I've noticed that we houdini users (who are not lucky enough to have access to shaders dveloped by giant companies) lack an overall dense (almost pyroclastic) cloud shader that shows the distinct features of puffy cumulus clouds. After a through searching both in web and odforce i've seen that a few people also inquired on the same subject but it was inconclusive. I've decided to use this post as an idea dump to possibly implement a new shader or track your opinion on the subject. During the searching i've realized that distinct features of dense clouds are achievable by either using a very high number of internal light bounces or by faking them. I have seen that dark edges are the most prominent feature of the dense clouds since the other effects as transmittance and high forward scattering are already studied and implemented in shaders. To assess the current state of volume rendering other then mantra i've done a couple tests with several renderers in maya and also tried the new terragen 4.2. The most beautiful (simulating a real cloud light) is the hyperion render. Terragen 4 clouds are also very realistic and detailed (http://terragen4.com/first-look/). Arnold seems to be the best commercial option out there and is very good in giving the edge darkening but fails at details in dark areas (which is highly visible in hyperion) but i think these areas can be compansated with additional ligths. Redshift render is blazing fast but no where near the realism. In houdini i have used pbr with 50 volume limit, 5x5 samples, volume quality at 2 with a standart volume cloud shader. I have just started to see dark edges but even rendering a very small portion of 1920x1080 image took me about 10 minutes ( 2xE5-2680 v3, 48 cores total) . For speed comparison, redshift was the fastest with a couple minutes, arnold took about 10 minutes, terragen is said to be around an hour for a very heavy cumulus cloud. No information about hyperion but since wdas has a 50.000 core farm it shouldn't be a problem. Mantra was the worst with a projected couple hours of total render. Below are the sources i found for future reference for myself Oliver also asked about a cloud shader and Mike Lyndon says he has implemented a shader before (https://forums.odforce.net/topic/17900-cloud-shader/) . This is the most prominent one and is the one i will be implementing. The thesis of Antoine Bouthors that Mike says he has implemented (http://evasion.imag.fr/~Antoine.Bouthors/research/phd/thesis/thesis.pdf) . Beautiful mie scattering solution by Matt and the base for my shader (http://mattebb.com/weblog/rendering-clouds-with-the-mie-phase-function/) Odforce user Andrea was also interested in such topic and has some ideas in it (https://forums.odforce.net/topic/24831-cloud-shader/) Modelling aspect of clouds (https://forums.odforce.net/topic/12923-pyroclastic-noise-demystified/?page=2) Siggraph presentation by Magnus Wrenninge (http://magnuswrenninge.com/content/pubs/VolumetricMethodsInVisualEffects2010.pdf) Realtime clouds for horizon zero dawn by guerilla games. realtime but has really nice implementations (horizon zero dawn real time clouds) A hefty paper from Hyperion developer Yining Karl Li (https://blog.yiningkarlli.com/2017/07/spectral-and-decomposition-tracking.html) With the directions i gathered from Mike Lyndon's post i have started implementing the photon map approach. I have already implemented a henyey-greenstein phase function and added the contribution by radiance photons. Now i will try to implement the ideas presented in the thesis of Antoine, with high focus on cumulus cloud rendering (ch. 7). Attached is the current state of shader (cloud_shader.rar) I am also interested in GLSL implementations for viewport and cloud modelling tools but i guess this post wil be mostly about a shop type implementation. anyway here is a simple glsl implementation work and i am open to every feedback https://forums.odforce.net/topic/32197-glsl-pipeline-in-houdini/?tab=comments#comment-190945 I am definitely not an expert on this subject, so all input, ideas, criticsm, and source is welcomed. Thank you. Hyperion Render (wdas_cloud_hyperion_render.png is Copyright 2017 Disney Enterprises, Inc. and are licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License ) Terragen 4 Render terragen_4_render.tif Houdini Pbr Render (the little part on top took 10 minutes to render so i left it unfinished) Arnold Render Redshift Render
  17. best way to add fields to volume

    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
  18. Hi guys! I am working on a project that needs a spirit moving through a scene, it needs to be like flowing smoke with a glowing light effect so that if reflects on objects in the scene. I cant work out how to emit light from the smoke and move with the animation, i have been playing with both volume lights and geometry lights but i cant get either to move with the animation, they both stay at where the animation is on frame 1. I have tried selecting the volume and creating a volume light from that, and also using the original animated geometry before it was turned into a volume and making a geometry light from that, but neither use the animation. Can anyone suggest what i am missing or doing wrong? Or way to get the smoke to emit light and use the animation to move? I have attached a r&d scene file and a play-blast of my problem as it stands at the moment, any help would be really appreciated! smokeLight_001.hipnc smokeLight.mp4 smokeLight_001.hipnc
  19. Collision object in Pyro sim

    Hi everyone, I am working on a smoke simulation and i have imported my collision object with source volume into my Pyro sim. No matter how much I increase the smoke divisions as well as reducing the voxel size on colliding geometry I still get jagged edges when smoke interacts with it. I have attached a screen capture here to make it more clear. Is there any way to smooth the jagged edges or am I missing something in the process? Any tips would be greatly appreciated!
  20. I am doing pcopen in cvex to to render points as volume but for some reason I am not able to scale the density as much as I want. It looks like it is clamping the density values and doesn't allow me to go higher. When I use smaller IFD bounds this problem fixes itself but also it cuts my overall object. Also vex volume procedural doesn't seem to work with new mat context. Thanks for the solutions, Alican
  21. Smoke Effect skin

    Hi Everyone I was wondering if someone knows how I can create this effect I have just done a simple smoke simulation, but I do not know how to make the inside: also, if anyone knows, I am trying to create this object with the exterior like the purple surface, but the inside to look like this: ANY HELP WOULD BE APPRECIATED
  22. Smoke Effect skin

    Hi Everyone I was wondering if someone knows how I can create this effect I have just done a simple smoke simulation, but I do not know how to make the inside: also, if anyone knows, I am trying to create this object with the exterior like the purple surface, but the inside to look like this: ANY HELP WOULD BE APPRECIATED
  23. I'm trying to render out a volume inside of a clear object and running into an odd materials glitch. To test I have created a box with a default glass principle shader and a VDB volume of the same box shrunk down inside the box which I have colored blue. Rendering with Mantra, if the volume is inside glass box, it loses all color, but outside keeps it. There is one other issue. I really want the volume to filter the light to color, so the shadow/rays coming out of the volume should be roughly the same color as the volume, as opposed to being black. volumeTest.hipnc
  24. Hello All, I'm newer to Houdini, and working to jump into setting up some simple/fast solutions for wrapping particles around a mesh. Not sticking to the mesh, but flowing over. I'm a professional Nuke compositor with general experience in Maya, so will understand most terminology, but certainly completely new to Houdini, so open to all suggestions and breakdown's of the principles. The end goal is to drive a curl noise vortex up in Y, and place geo within the field that the noise will wrap and flow around. I have attached my test HIP file. I've been trying to combine this tutorial's use of the cross product and XYZ distance, with the VDB setup from Entagma's Curl Noise tutorial. Other than there being a good possibility I'm on the completely wrong path for this type of effect, it seems I may be confused on properly using the cross product in the VolumeVOP. The attached file doesn't touch properly adding or multiplying in the curl noise, because I want to correct my issue with the field to begin. Thank you all for your time, patience and help. My Best, Josh curl_noise_trailsTest_003.hipnc
  25. Can't render particles as volume.

    Hi everyone. I am trying to render Houdini particles as volume. Volume appears in the viewport but cant be seen in the render. I created white water using shelf tool in another new scene and copied the network into my file. I am clueless about the problem. Please help. Thank you.
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