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Found 124 results

  1. Hey guys, I have a quick question about the polygon soup meshes I'm getting out of Houdini. I'm getting mesh popping when I convert it and send to C4D for render, they look like the attached IMGs. I included my set-up in there as a rough guide but I think there's something I'm really overlooking. I'm kinda new to Houdini still and would really appreciate a kick in the right direction of how to solve this in terms of the way I'm approaching 'skinning' the particles. Thanks

    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. Hello everyone, I have just started using Houdini but I'm stuck following a VDB tutorial from Entagma with my own object. Basically, I have a kind of barchart created using a custom attribute H on the primitives of a grid via a polyextrude node. I can't transform it properly into a VDB regardless of the voxel size if I use fog or distance. Yet it works if I add a custom surface attribute on the VDB. Now that I have my barchart volume, I cannot VDB combine it with other volumes. I tried specifying the group and play with all parameters but I have this error: I have linked the project to make it clearer. Thank you very much for your help. grid.hipnc
  4. Move points through the "center" of a SDF

    How can I move one particle each through the center of these SDF pipes? I think I will be able to define starting points with a volumeslicer (better ideas welcome!) but I am uncertain about moving them. volume_to_particle.hip
  5. Hello, I'm trying to figure out this thing about UVs and polygons from vdb in Houdini and so far so good except for the new and nasty UV seams that are created after the transfer is done through attribute from volume. Maybe someone can shed a light on this, it would be much appreciated. So, i created a simple scene with the pig head, converted it to vdb (from polygons) and then back to polygons. My intention is to transfer the UVs from the original head to the converted polygons from vdb, just for studying purposes. I used the attribute from volume node and it worked almost great, the UVs are transferred nicely but with nasty distorted seams. Even though the UV seams get lost in the vdb conversion, the approximation performed by the attribute from volume node is quite good but i cannot imagine a solution to solve the distortion on the seams, at least through this approach. The attached images show the comparison between the original UVs and the transferred UVs to the converted polys from vdb. Any idea about how to clean the erratic distortion on the seams? Or, is it even possible to do such thing? Thanks.
  6. Pyro to Maya

    Hey magicians, What's the best pipeline to export pyro to maya? I'm working at houdini scale and I think maya scene is x1000 so I'm worried that the smoke probably will look bad. Any tips will be really appreciated Thanks!
  7. Ground / Terrain Collapse Effect

    Hello all, I am looking at this amazing fx made by Axis for Halo e3 2013. Studying the reference ( the terrain fx ), I thought to approach this using RBD fracture to drive a second sim layer of pop grains (sand). However, I am also thinking maybe I could use vdb+volume vops to mimic the motion. and for the second layer, perhaps using just particles emitting in focus areas. I would appreciate your thoughts on how to approach this. GroundCollapse_Reference.mp4 @MENOZ would love your input if possible.
  8. Hey folks! I was hoping to gain some understanding on how I might 'mask' out areas from the advection process. I have a recursive growth setup and want to add some objects into the scene where the growth will react to and grow around it... Im not sure the best way to go about this so im not subtracting the colision surface from the growth vdb every frame... ideally some vops setup to multiply the negative space of the collision geo with the direction of growth (velocity) so that it zeros out as it nears the surface. Im using a modified version of this setup i found on the forum. attached youll see the surface i want a collision with. http://fx-td.com/content/misc/recursive_growth_v2.hiplc Many thanks!
  9. 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.
  10. Combine clustered pyro into one domain/object to export for render in v-ray Maya? Thanks in advance.
  11. My hang glider ran away

    Always wanted to make a cloudscape. Rendered in Octane. About 48 mins on a single GTX 1080. 1600 x 2000 pixels.
  12. 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
  13. Hey, I recently played around with the network settings, among them was enabling jumbo packages. In the following tests i did, i noticed that Writing a VDB over the network was significantly slower than other formats(bgeo, begeo.sc, obj, etc.), for me on my current network writing a VDB is about 1/5 of the speed of other formats. Local write test show minimal difference, and when writing a vdb over the network it "waits for queued writes", it seems to be a network issue and not tied with the actually creating the VDB. My current solution is a post-frame script that moves the frame to the server after writing it locally and that seems to be about 3 times faster. But i was wondering if anyone could explain it or maybe have a better solution? I am defentlitely Houdini novice so i might just be completly be missing some env variable or the checkbox: MOAR SPEED!1!!one1! [ ]
  14. I learned that you can create a vdb from the camera using the vdb node, set to "From Camera". This shows you the camera frustrum as a bounding area. I want to turn this vdb into polygons. my failure to do so reveals my lack of vdb knowledge. The vdb From camera tab is set to fog volume. I gave it a name of "density" and used a vdb activate to give a value of 1,1,1. I tried to use a convertvdb node to convert to polygons, this didn't work. i'm misunderstanding something here. help would be appreciated.
  15. VDB sop

    What is the purpose of the VDB sop? The only time I have seen it used is with volume rasterize particles when creating white water. What other times would you use it? Also, what is the point of the visualization? The documentation says the node is creating empty vdb's so what is there to visualize? Also, I can't get it to actually show anything other than the bounding box showing the voxel size. thanks in advance.
  16. Hey guys, i have an alembic animated file (there's no deformation) and I have to convert this object to a vdb mesh (vdb from polygons >> convert vdb). I did it on a static frame (using timeshift) and now i'd like to copy the original animation to this new mesh. A copystamp does copy the position but not the rotation. Can you guys help me with this? Just to make things clearer (this is not the original scene, i'm kinda faking it so i can share here) this is the alembic character animated: then I made this new mesh from it: i need to transfer the position and orientation from the first one to the second one. I guess i could make it with a packed object since it have just one point Thx! RnD_copy.tansformation.v1.01.hiplc
  17. I would like out to export out a Smoke Trail simulation as a VDB sequence so I can import it in a different package. Because the smoke is clustered I can't figure out how to export it out. It only seems to export out one cluster. Setting $CLUSTER in the Rop Output path doesn't do anything. I think that variable is used if you distribute the sim on different machines. I only have 1 machine. Redshift displays there are multiple density channels and the file size of each frame get larger even though the displayed cluster is empty on further frames. I'm using the Smoke Trail shelf preset as a starting point. Eventually I'd like to simulate a long smoke trail along a moving object. Unfortunately I couldn't find any information about this. I'm using Houdini Indie. Thank you for your time.
  18. 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
  19. 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
  20. 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
  21. 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!
  22. 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
  23. 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
  24. 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
  25. 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