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Found 107 results

  1. Vdb grups?

    Hey magicians, I have a setup that make some blobs growth, but I need them to growth in a different speed each one, I tried making groups out of vdbs to control each one by time offset with no luck, also tried playing with different vdb names. Any tip on how can I affect the speed of each blob separatedly? Plan B will be making each vdb growth separatedly and then play with vdb combine, not sure if I'll get the same effect but will give a shot. Here is a sample gif and file to illustrate my issue Thanks in advance! growth_hip_for_offset.hip
  2. Smoke changing color

    Hello! I am new to Houdini, but am attempting a fairly complex effect. I need to emit smoke and particles from a piece of geometry, with these specific characteristics: The smoke and the particles must start off as grey. The particles should be emmited from a black-and-white mask that is mapped onto the emmiting surface (white=emit, black=no particles emmited). This texture should be animated. The color of the particles should be defined at particle birth by another moving texture (an animated fractal noise, for example). At 1/3 of their lifespan, the smoke and the particles would change into two different colors (blue and pink,. I am guessing that the right way to do this is to start with the particles, and then copy the color attributes onto the smoke. The two should move together, so... should I first do the smoke, and them move the particles along the same forces? Any help would be greatly appreciated! cheers, Diego
  3. Hi everyone ! I encoutered an issue with my growing VDB, in facts I want to use it in order to drive a recursive growth effect (based on that setup https://www.sidefx.com/gallery/recursive-growth/), but when I wire it to the solver SOP, it take only the start frame of the solver SOP and it doesn't care about the "animation" of my VDB. Have you already face this problem and is there way to tell to Solver SOP " Hey you take into account my growing stuff". Here is a HIP file to illustrate my issue. Thanks. Yan. issue_vdb_solversop.hipnc
  4. VDB smoke uv mapping

    Hi guys I'm trying out some stuff for my upcoming project and was wondering how to make uvs for smoke converted to poligons, so that they would remain stable rather than jumping around every frame. I found some info on using dual rest position, however I'm not sure how to tackle it, or if it could work with this approach. Here is what I have right now ( I'm not sure if you can see that, but there are scratches on the surface of the smoke which as expected change where they are every frame, the question is how to make them remain in place even tho the number of points is changing and whole thing is deforming) Here is the type of effect I'd like to achieve: Any tips are very much appreciated!
  5. Hi, I'm trying to pass the color from polygon to VDB, transform the VDB then apply the color back to polygon but I don't know how to do. I tryed to use "VDB advect points" but I can't figure out how it's working and if it's the right solution. Charles VDB_color_uv.hipnc
  6. Combine VDB vectors

    Hi, I was wondering if anyone knows any method to combine velocity vectors of x number of VDBs with an average operation. With VDBCombine SOP either Add or Maximum operation will not give me the correct result because the add will put one vector on top of the other and the maximum will just keep the vector with the greater length. I can produce average using a volume wrangler and the avg() vex function but then I am limited to 4 volumes. cheers, C
  7. Hi all, Question, i'm trying to convert my polygons to vdb and back, to create a Particles-to-liquid effect. The only problem is, that i don't know how to activate the vdb when it enters the area of change. Someone any idea on how to fix this problem? I put my file in here and a screenshot of what i want to achieve. Thanks in advance! Greatz, Christof 08_Particles_To_Mesh_V01.hip
  8. Particle movement and collisions?

    Hey guys! I'm trying to make some floating particles inside a geometry. I need the geo to be a collision object and the particles to kinda have a buffer area before they touch anything, not very obvious but enough so nothing actually collides. However, I'm having trouble getting the particles to actually treat the geo as a collision object, and also stopping some of the random ones that like to go super fast. I thought that the popspeedlimit would the trick for the fast ones, however, it kinda clamps the whole speed of all the particles, rather than clamping the velocity of the fast ones. Anyway, here is the scene file with the alembic, if anyone has an idea of how to fix this please let me know! underwater_particles.009.hipnc blockoutForSim.abc
  9. 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
  10. VDB banding/stepping issue

    I was wondering if anyone had a quick answer to this issue. I'm applying some cloud noise to a cloud and then converting it to geo. No matter how high-res I make it I still get a lot of banding (or stepping?) after I apply the noise. Am I not approaching this right? I attached a hip file if anyone wants to take a look. vdb_noise.hip
  11. Hi, I'm trying to remove part of a sphere with a bunch of other spheres that I converted to vdb then to polygon to use like metaball and have a single geometry to use to "cut" the other one. Thinking (silly me) it would make it easier. if I switch the input of the Boolean node it kind of work, but I need the reverse of it. It was working great with the cookie SOP before. but I'm guessing new node require new workflow (which is fine, I just haven't understand it yet).:) The boolean node is giving me a warning "NonManifold edges in solid...pnumbersnumbers" I added a Clean sop afterward to try to fix it but no luck, I included my hip, if anyone of you nice people could help or point me in the right direction it would be much appreciated. I also attached the intended result, which I got with the cookie sop a long time ago. thanks SplashScreen01.hip
  12. transfer Cd to vdb from particles

    I wondering if this is even possible? I'm animating points through a solver and then turning them into vdb's. I want to apply a random color on each particle. Everything seams to work until I convert to polygons. I tried to apply an attribute transfer after the convert but as you can see in the attached image the scale is off? If anyone can provide further assistance... It would be greatly appreciated! (I also attached a reduced file since I cannot send the actual scene) Thanks, vdb_HelpMe.01.hip
  13. Solver on scattered points

    Hi All! I think this is my first post, so thank you for all the info shared here - I have a sphere with scattered points (in texture space) and a map that makes propagation of the points over the sphere. - I have a solver moving this points over the sphere. The problem is that the solver just move the points generated in the first frame and I want the solver to be acting over the points created over the frames. I assume this can be a stupid question Thanks in advanced! Domingo.
  14. VDB creep using solver

    Hi everyone, Just wanted to share a little something I worked on yesterday. I created a VDB creep within a solver and for now the issue I have is birthing points at different times and adding them into the solver. For now they all get created at the same time. Still trying to figure this part out https://vimeo.com/249245842
  15. Smoke Solver Collision on Type

    Need a bit of help on a problem for a client, ( on an NDA as well ). Basically, I have a pipeline that shoots to Octane in C4D for the VDB usage and the smoke sim I made is fine and they are head over heels for it but the type (in the smoke) in the first frame is too pixelated for them and not high res enough. I've been trying to find the right amount of density and type space to keep the titles as sharp as possible but when I put them into C4D and play around about it's still exported in Alpha somewhat pixelated. Any ideas? I have a sample hip of the pig had at a reasonably replicated density to the pig but I need it to be more stoic. Smoke_collide_pig.hip
  16. Hi Everyone, I am still new to houdini and I frequently run into the following problem. WhenI use VDB volume for collisions in houdini Particle or Flip sim, particles collide with the bound of VDB volume instead of actual VDB shape. It kind of creates a boundary around VDB and uses that boundary for collision. Its visible in the viewport in orange color (yellow color in the provided SS as d object was selected when took SS). I often get this issue and I dont know what I am doing wrong and how to solve it. Even If I use shelf tool the problem still persists. If anyone of you have ran into this problem then please let me know how u solved it. thank you for your time. Cheers!!!
  17. Hi ! i'm trying to get volume data from points attribute pls see the attached picture in this case i set an attribute to some value and want it to be sambled into new VDB volume. it works like surface "wrapped" around my points (red area). and it's empty inside, although there are points inside with the attribute set to positive non-zero value btw it works fine when i set vdbfromparticles SOP to Fog VDB - it fills all volume where points exist Is it possible to sample any arbitary attribute into VDB like Fog VDB option does?
  18. Hi Guys, I want to scatter some points on a growing and deforming vdb mesh. These points shouldn't jitter on the surface and look like they are moving along with the surface. I have attached a basic file similar to my actual setup. Basically, I am going to render these particles as bubbles on top of the mesh and I want it to be quite dense. I haven't been able to figure this out and couldn't find much help online. It would be great if you guys can check it out and help with a response. Thanks vdb mesh vdbscatter_v01.hipnc
  19. Meshing Small Splashes

    Helloo, I'm working on some small splashes etc. For a project. And I'm at a point where eradicating mesh jitter is near impossible at the scale/amount of particles I'm using. The splashes are small and need a more chunky look, so I cant just up the resolution particles wise and hope that it meshes better as this completely changes the look. (The look I'm after isn't super high res realistic splashes at all as this is for a texture going into games) Ive tried meshing manually via VBD from particles instead of the default particle fluid surface - VDB from particle fluids - in combination with other vdb operations. Ive also tried point replicating so each point I have is 5 rather than one in the hope it reduces the likelihood of jitter and particles are closer together and theirs a higer count. Ive also tried upto 3 substeps in the base sim in the hope it maybe has more particles between one another. It seems almost silly when I've had the simulation as I've wanted very quickly but cannot get a small splash mesh without jitter. (Even tried motion blur to ease the effect but needs to be very strong to work and then smears the render more than getting rid of jitter) Any tips or ideas on the matter would be great (if I happen to solve it in the meantime ill post a file or at least a good description of how I got their eventually) - I have a feeling it may come down to trying every value possible in the particle fluid surface node or even animating certain parameters in their
  20. I am trying to get some temperature data that I have calculated on the output of a particle simulation to make it work with the pyro shader, but I can't seem to get it to transfer. I am using Volume Rasterize Points to get the particles into being a volume, which is working really well, but I can't seem to get anything but the density field filled. The node supposedly takes point attributes and fills a volume field with the data if it exists as both a field and a point attribute, which these do, but I keep coming up with empty fields. Failing that, I tried to brute force them over using Volume from Attribute, which I had successfully used elsewhere in the scene, but to no avail. Still giving me empty fields. This has started to become quite vexing, as I think it should be working how I have it setup, and it isn't. particleTest1.hip
  21. Hello, I have a problem that I'm not really even sure how to articulate. I have created a fog volume using VDB from particles and this will be used to create a landscape that looks like snow. I also have a train track made out of basic polygons and the idea is that the tracks are on top of the landscape and where the tracks meet the landscape the volume should flatten out so it looks like the tracks were laid directly on top. I want the landscape to plateau where it meets the tracks. I have explored converting the volume to a polygon, using an attribute transfer to create color information that can be transferred from the tracks to the landscape, I tried sculpting as well, but I'm coming up against a wall with my houdini knowledge. Does anyone have any ideas? I've attached a scene file. Thank you so much. tracks_example.hip
  22. VDB to "tidy" geo

    Hi Been watching the Hive Siggraph vids specifically the procedural game level building At 40 mins 28 sec in there is a corridor that looks interesting and i can replicate a lot of it (because of the way it is described) but i cant understand how the vdb is so clean. On the left it is just possible to see a convert vdb node connected to what looks like a wrangle of some kind? Does anyone have some insight into what would be happening in this wrangle to get such clean geo? I have no idea... Thanks for any input Dave
  23. Hello to all... I have a scene where I have animated geometry written out and I bring it back in via a file sop. The animation is just of some rocks flying up in the air flying down inside some water. I'm using a vdb from polygons on the file and I'm bringing that into the dop network as a static object with the mode set to Volume Sample and pointing to the object in the proxy volume field . The problem I run into is when the rocks collide with the fluid, the fluid collapses. I can remove the proxy volume and reset the mode to ray intersect and things will be fine....I have tried to explore on how to fix this but I can't seem to find the solution... does anyone have any ideas? I can upload the scene later if needed. flip_tests.hipnc
  24. 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
  25. Hello. I have some problem with boolean SOP, when I Shatter model after Convert VDB to polygons, it just slices geo. Doesn't make separated pieces of geo. I tried to remesh and fuse geo before Shatter but it gives me nothing. boolean.hip
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