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EuniceC

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Everything posted by EuniceC

  1. FLIP simulation problem

    Hi, I have been trying to learn Houdini and have been doing a flip simulation of a boat moving across an ocean. So far, it has been okay, until I saw that spray particles were being emitted through the boat. It was then I realised that there are default water particles inside the boat even in frame 1. I have checked my boat collision geometry (the blue collision geometry and the purple collision guide inside the guidedoceanlayer node) thoroughly and I really do not know what's wrong. I thought that the collision geometry is what allows the particles to interact properly with the geometry, so does having a thin collision geometry affect the collision? If so, how can I increase the collision geometry thickness in the inside of the boat? I tried polyextruding outside but there will be an imaginary space between the outside of the boat and the water particles. I've attached the video here and my houdini file. I've cached some stuff out to make the simulation run faster. Can someone please help me with this?? I have been trying to fix this for the longest time. Nothing I've done worked and I've ran out of ideas on what to do. BoatGeo_Test4.mov OceanBoatSim2.hip
  2. Saliva Effect with wire solver

    Thanks Atom and wacool for the guidance! and many thanks to wacool for giving an example files on how to customise something like that. I ended using a mixture of cloth, FEM and wire to achieve what I want. It's a good start for myself.
  3. Saliva Effect with wire solver

    Hi, I am trying to create some kind of saliva effect from a creature's roar when it opens its mouth, something like this. I researched for quite a bit and understood that this can be done with the wire solver. However, I'm getting stuck at getting the constraints to work!! I created a line and made it wire object. Then, I use glue-wire-to-animation from the shelf tab to constrain the line to my model. I want to constrain the 2 end points of the line to the animated object. I can see the constrain but it is not moving with the animation. I'm not sure what I did wrong and how to fix this. I don't really understand constraint network since it's my first time working with it. Can someone please help? How do I constrain my wire object to an animated object? I also thought of scattering points of my model and use the add node to first create the saliva. But what I don't understand is then how do I define so that the points on attach from top to bottom rather than left to right. Any advice on this? Here is a reference video. What I would like to achieve is something very similar to this at 0.09s. https://www.markinglevfx.com/projects/6477328. Here's another one but the description was too brief that I still don't understand how does it go from wire to pop for dynamic and meshing. Thanks, Eunice
  4. whitewater setup on deformed wave

    Hi, I need some advice on how to create whitewater on a mesh? I created a deformed wave using a grid and Attribute VOP instead of the ocean tools. The reason for that is that I wanted my wave to curve in an unnatural way. I'm trying to set up whitewater, spray and mist for that wave at the moment and I'm not sure where to start. I can't just click whitewater from the tools because my mesh is not a flip sim. What's the best way to go about this? I thought of using vdb from polygons but then I'm stuck again and not sure where to go from there. Please help! Any advice will be appreciated! Thanks
  5. Looping Fluid Simulation

    Hi I made a water tornado, the movement is just like a tornado, rising from ground but I used flip particles and the pop axis force to generate the orbit and lift force. After a certain frame, I would like to let the simulation loop but without increasing the height of the water pillar. Basically, the pillar stops rising but the flip particles still behaves dynamically. Is this possible? How would I go about doing this? Thanks
  6. Hi, I generated a bunch of fluid particles on a wave and I used the particle fluid surface node to generate the necessary mesh to be rendered. However, on some frames, about 90% of the mesh disappears. This is pretty frustrating, Can anyone advice me on what's the underlying issue that makes the mesh flicker that way? and how to go about fixing this issue? I've attached the mov file that shows the issue I'm having right now Thanks mesh_flicker.mov
  7. Particle Fluid Surface Mesh Flickering

    I tried resimming many times but still the same. I'll try it again and this time I'll delete all the previous files too. When I flip book the frame with particles, they look fine though, it's just when I convert them to mesh. I didn't time stretch anything. This only happens when I use surface VDB option. It's fine when I use Surface Polygon Soup. Problem is it doesn't look nice if I smooth it out. I wanted that look exactly produced by the surface VDB option.
  8. pop gravity node

    Hi, I made a deformed wave and I turned a patch of it into flip object. I wanted the patch of flip to move with the deformed wave mesh, so I bypassed the gravity node. I then have a geometry colliding the patch of flip particles but the problem I have now is that, because I already made it zero gravity on the patch, the sprays formed from the collision is now floating in air. I wanted the spray and foam to be influenced by gravity so they fall back to the ground but at the same time I want my patch of flip to move along the deformed wave mesh. Does anyone have any suggestions on how to achieve this? Thanks
  9. pop gravity node

    The only way I can see this working is that I use pop wrangle and group them by velocity. so something along the lines like if (@v > 0), activate gravity. There's no gravity expression in VEX, I'm not entirely sure how to go about giving it a force. This is my file here. flipCollide.hip
  10. mist on wave problem

    Hi I have a problem with mist generation on my wave. I used a vdb and made it a flip object and then generate mist from there. It looks very weird and there is some problem with my mistsource node. Can anyone please look at the hip file attached and give me some advice on this?? WaveDeformer2.hip
  11. Ocean mesh flickering problem

    Hi, Here is my WIP for a deformed wave. I need some feedback on this. The ocean surface is flickering quite a bit, what's causing this problem and how should i go about fixing? Is this a shading problem or something else entirely? Thanks
  12. Deformed wave WIP

    Hi, Here is my WIP for a deformed wave. I need some feedback on this. The ocean surface is jittering quite a bit, what's causing this problem and how should i go about fixing? Here's the video:
  13. Hi, I am currently creating a wave deformer. It is a mesh and I was using the delete node to manually delete the extra surfaces of the mesh. (for example if I only want the curved part of the wave but I need the grid to be long in the first place to generate it) However, my point trails became weird and this is affecting the result when I use the intersect VOP. I suspect that the problem lies in having some deleted points in lines like in the mesh.png image. Is there a way to make sure you can select the straight lines? As you can see in the attached images, my point trails extrude all the way out of the mesh. How can I fix this problem? Thanks
  14. Creating waves with vertical lines

    Hi, I have a question about the ocean spectrum node. I have created a deformed wave using a grid with ocean spectrum and ocean evaluate node. I can change the ocean spectrum wind direction setting to achieve the kind of look I want, which is to have the vertical lines on the ocean surface, something like the image below. But if I only do that, the waves direction is still wrong, they are moving sideways. Is there a way where I can create this effect with chops moving in the right direction? I thought perhaps I should create another ocean spectrum and put it on top of the first ocean spectrum. This is pretty urgent, does anyone have any suggestions? Thanks!
  15. Creating waves with vertical lines

    Yes that is exactly what I meant! Thanks a lot!!
  16. whitewater setup on deformed wave

    This is amazing! Sorry for the late reply. I have been working on the wave scene and have finally achieved a desirable look. Special thanks to @moneitor for your help!
  17. Creating waves with vertical lines

    Thanks for the suggestion but I've already tried that. I rotated my wind direction to 90 degrees, I get the vertical lines. The directional bias and directional movement just makes it move more in the wind direction. In the image above, even though the waves have those vertical lines, the water particles are still moving forward to create the breaking wave. That's the effect I want to create, without converting my whole mesh into flip as that would make the simulation too heavy to be computed. In your example hip file, the waves have the lines but it's moving in the wrong direction. it's basically what I want to fix.
  18. whitewater setup on deformed wave

    I tried something using vdb and getting the cross product of velocity vector and gradient. I then used Ray SOP for the whitewater emitter. I used "OUT_EMITTER" from oceansurface node as my whitewater emitter. I still couldn't get the effect of whitewater where it moves more randomly but at the same time follows the movement of the mesh. At the moment all they do is fall downwards. I tried various methods but it's still doing the same thing. For my flip, I used "OUT_VDB" for my flipfluidobject. I want to achieve something like the one in the reference picture, or at least something similar. WaveDeformerTestQuickMask_edit2.hip
  19. whitewater setup on deformed wave

    Actually, the waves are still and I was thinking of generating the whitewater particles through the movement of the cusps. Clearly that was not enough and it probably wouldn't work. I have animated the wave to fit what I want and modified my wave accordingly to achieve the curvature scatter points. Now it's emitting particles, I just have to make the points float. I'm think to make the particles float, I have to create a surface VDB on the mesh and connect to the pop network? Here is the updated file WaveDeformerTestQuickMask_edit2.hip
  20. whitewater setup on deformed wave

    That's great. I will experiment with it. At least now I have an idea of which direction to work towards. Thanks a lot! Do post your example if you have time to make something over the weekend
  21. whitewater setup on deformed wave

    Thanks for the reply! Would you elaborate more on the part about creating a mask? I have attached my hip file here so you can see how I've set up my wave. I was thinking perhaps I can use the shelf tool (Flip Fluid from Object) and make a flip sim from my scattered points there and then just use the whitewater shelf tool. I'm not sure if this will actually work. From my understanding, the scattered points are already the particles? WaveDeformerTest.hip
  22. Blending 2 waves together

    Hi,I have used the attribute VOP to create 2 separates wave deformers. I would like to blend these 2 together to get the shape that I want. I tried using different attribute nodes but I can't achieve the effect of blending the meshes together. How do I go about doing it?I have attach my nodes network and the image here. You can clearly see that the meshes are separate, I want to combine the mesh. I tried joining the 2 attribute VOPs one after the other but that only increases its amplitude and nothing else, I want the 2 mesh to join at different position so I get a v shape effect like the png image I show here. I thought of perhaps multiplying the 2 wave matrix together by using the attribute wrangle node but i'm not sure how to call out the VOP variables individually when both waves' output is the same (position P). Is there a better way to do this? Any help and advice would be appreciated, Thanks!Eunice
  23. FLIP simulation problem

    Thanks for your reply! I will try out your method. Here is also a hip file with the locked geometry and the geometry file itself. I didn't really worry about the fluid underneath the ocean that is within the boat until I saw that it gave me problems when I have big collisions with the waves. I have simulated a stormy ocean, so as the boat collides with the big waves, some spray particles are leaking from inside the boat and it looks pretty obvious in my point of view because it occurs on both sides of the boat, so no matter which side I twist my camera to, I can still see the leak. I attach the link of the test I did here. OceanBoatSim2.hip boat_v001.bgeo
  24. FLIP simulation problem

    Here, the purple wireframe is the collision geometry of the boat and the black mesh is the particle fluid surface. I do not understand why does the black mesh follow the collision geometry to a certain extent and then completely ignores it.
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