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  1. Today
  2. problems with collision and alembic

    Try disabling the geometry visualization to better see if the actual collision gemetry is consistent as a first step, it is possible that there is a discrepancy betwheen the two!
  3. Cut a moving object with solver ?

    Hi Antoine, to continuously remove parts, it's more reliable to do the subtractions in a voxel field rather than immediately on the mesh. saw.hipnc
  4. Redshift users, post your tips tricks here please!

    Hey everyone, I think i need some help with volumes rendering I am building a scene which has both neon lights that create a nice neon-like foggy look and regular pyro volumes. I was wondering if it was possible to selectively activate the “volumetric scattering” options in the Redshift Rop in order to make only some of the lights in the scene create the said foggy look and still have regular volumes render as normal smokes etc. Thank you for your time Frankie
  5. Cut a moving object with solver ?

    My problem: simulate a table saw; object come to one side of the blade and ends up to the other side of the blade with material removed where the blade touched the object. My strategy: boolean subtract the blade from the object at each step of the trajectory.
  6. Genetic Algorithms in Houdini

    I am not sure if this is the appropriate forum. I recently wondered how hard it would be to implement genetic algorithms in SOPs. The particular example I was curious about was if I could turn a box into a sphere by optimizing for a target function that maintains volume but minimizes surface area. Overall, this was easier than I thought and did not involve all that much code. I ended up recording a video that explains this: The underlying motivation was to get this working in PDG but I figured I had to start with SOPs first. Let me know what you think.
  7. Yesterday
  8. Cut a moving object with solver ?

    @AntoineSfx Make your box a softbody ?
  9. Cut a moving object with solver ?

    I don't quite understand your strategy or your problem. Please post a hip file.
  10. Cut Copies

    Thanks guys I appreciate the help!
  11. I have a keyframed animated box and a cutter (a smaller box) on its path. Using solver, I don't manage to have the cutter remove stuff from the animated box using only previous frame and the cutter. I managed to do it like this, but I wonder if whether it's a good practice or not: I got the transform from the keyframed box using a matchsize to move the previous frame.
  12. I think it depends on the render you want to use. But anyway, you're going to have to use TP. With 6 million particles, it's not really a good idea IMO. Also I think I remember that it is imperative that there is at least one particle from the first frame in the alemebic file.
  13. Frozen Particles

    thanks for your help kleer001 I will apply your advice to optimize the piece. I tried to disable resize_container> Max Bounds> Clamp To Maximum. But the particles are still freezing. The only thing I try to achieve is that the particles that freeze when they reach the top fall with the others. The rest seems fine. Sorry for my ignorance, to apply the Alpha do I need a SOP VOP? How can I do to use it? This would not make disappear all the particles of the base that do not move? I try to get something similar to what Simon achieves in the second 14 of this video Thanks again
  14. Increase FLIP viscosity with particle age?

    Yup, someone pointed that out on the SideFX forum. Beautiful, and big and obvious and staring me in the face the whole time. Thanks!
  15. Motion Blur pass with mantra issue

    iirc you will have to enable velocity blur on the geo, enable motion blur in the mantra rop and disable 'Allow image blur' v_pass.hiplc
  16. Increase FLIP viscosity with particle age?

  17. Increase FLIP viscosity with particle age?

    Also, someone on the SideFX forums pointed out that you can add an age attribute right there on the FLIP solver. Hidden in plain sight.
  18. Increase FLIP viscosity with particle age?

    Thanks, gents! Evan, your example was great. I replaced with viscosity wrangle with a simple f@velocity = @age * [a number] and it did just what I wanted. Don, I missed something on yours, but I can tell the error is mine. I've got screenshots of the node trees. I can tell the Geometry VOP is added in correctly--if I crank up the offset value (the parameter I added going into the add) it does alter the viscosity--but trying to multiply the age * the bound viscosity * a parameter multiplier isn't doing anything. What did I miswire? fliptest.hip
  19. Optimize Pyro Container, H17

    Been trying to crack this one since they changed the sourcing. Few variations here. Done in 17.5 vel_test2.hip
  20. Increase FLIP viscosity with particle age?

    hey, here is a file. It shows a way to make a birth & age attribute. hope this helps------ flip_age.hipnc
  21. Increase FLIP viscosity with particle age?

    Hey, just use a geometry vop, bind the viscosity and multiply it with the age, and then export the viscosity. You can add another multiply with a constant to tweak values and get the result you want ! And don't forget to plug it into the particle velocity ! Cheers,
  22. How would one increase FLIP viscosity based on particle age, to get a thickening/coagulating effect? My searching only found one how-to from 2012, which doesn't work in H17+. I understand setting viscosity by attribute, but it appears FLIP particles don't have an age attribute, so I'm not sure how to shoehorn one in there. Thanks!
  23. I get it. Being effective and all is great but rotating the container is not really a good idea. Spectrums are projected from Y-Axis. Also the SDF Vol and Vel Vol are dependent on it. Rotate it but I still dont see the point of How being Effective??? About the Container Size, that have to be big enough to calculate the Splashes and the following Wake. You can try the Sink Vol Idea if you really wanna TRY it out. Cheerio.
  24. smoke trail render

    Copy part of density, apply gradient based on distance to object and convert it to temperature and you got fire at render
  25. Cut Copies

    Hi, you can use a pointcloud node aswell. After this you can apply a volume wrangle on it, which is more comfortable to define scalar fields. Now you can use volume convert, which converts your cloud(field) into an isosurface. The standard convert + fuse will create polygons, which can be used for boolean (or other) operations. Applying for each node with different iso levels, will give different iso surfaces. The main problem is finding the right iso function and parameters. There are many possibilities. And even if you have the right values the effect needs more to look equal. If interested, here is a rough approach getting iso surfaces iso_X.hipnc
  26. smoke trail render

    I responded to your post on sidefx, but if you used the smoke trail tool, then you are gunna get a smoke sim. Your picture would be a pyro sim.
  27. I was just using a test curve to make it easier. My thought was that if I could have a rotated container then I could focus on the wake of the boat instead of simming a larger container, being more efficient with my simulation. But I think I'll just drop it lol, it doesn't seem very popular. Thanks anyway
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