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Everything posted by Farmfield

  1. Magical fire

    Here's the basic setup for that... particles.hiplc
  2. I don't think you updated the file, lights are still there and it's on frame 75 when opening the scene file. About your render, a nuclear explosion is a 300m/1000ft ball of plasma that will move upwards in one piece, cooling slowly, and as it's so hot it will remain relatively unaffected by outside forces, it doesn't break up (as in your render) as it runs out of fuel, like a normal explosion - and that's why it creates that specific type of mushroom cloud, it's from the vortex created around the rising ball of plasma. A very similar thing, in regard to fluid dynamics, is a bullet exiting a gun. Much like the nuclear explosion, the forces created by the exhausted gasses and the bullet are so much bigger than outside influences, you have this very clean formation of multiple vortices being created, some from the gas movement, some from the bullet... This slowmo shot from Mythbusters shows that very clearly.
  3. Optimal size for pyro simulations?

    Houdini units are in meters so a 2 unit high box is 2 meters high and as the DOP solvers are set to the Houdini unit scale, just keep to real measurements and you will get the correct behavior from your simulations. Now, if you don't use the correct object scale, you can compensate for that using the scale parameter in DOPs, but I would propose it's "better" (easier) keeping to correct object scale in the scene.
  4. Forces For Cloud Object?

    About the Cloud Noise SOP (VOPs are Vex Operators), you can basically set what that does up one Volume VOP, once again, it's pretty straight forward stuff. And just generally in regard to using VDB's for creating non-dynamic cloud type setups, I would highly recommend this awesome tutorial by Andreas Vrhovsec's from Digital Tutors... He uses some really neat tricks in that for setting up very cool, non-dynamic cloud movement.
  5. Forces For Cloud Object?

    Playing around now, I must say VDB's are much quicker, the cloud tool feel very sluggish in comparison... VDB.cloud.text.test.hiplc
  6. Forces For Cloud Object?

    So I played around for a while and it really is as simple as using the shelf tools on your cloud setup - though you need to delete the create volume SOP and mess about with the grid settings in DOP's to match your cloud setup - but it's fairly straightforward. Don't know if it's even worth posting the scene file...
  7. Forces For Cloud Object?

    I haven't messed with this type of setup but I imagine the thing here being, you need a container - like a domain in Blender - and then you populate that (which basically equals an attribute transfer) and then you simulate that setup. I'll see if I can do a quick set it up here and if so, I'll post a scenefile.
  8. @Atom Just press escape as soon as the scene opens to stop the simulation and then jump to frame one. Another tip is do disable the lights to stop them for calculation the viewport render. @OP So first off, in regard to my reply ti Atom, above - when saving scene's with simulations, be sure to be on frame one, else, opening it, it'll start simulation and locking up Houdini directly. And I don't know what you have set up here but it's insanely heavy and if I enable OpenCL I get instant OpenCL errors and Houdini crashes. Not to be rude but I suspect most who opened scene took one look and judged it a potential rats nest and closed it down. We have no point of reference to the methodology you used setting this up at all so unless you're in production and get something like this, most - myself included - won't start digging trying to figure out what the hell it is we are looking at.
  9. How to merge the two meshes?

    ^ LOL That's what I love with Houdini, 629 solutions to any problem.
  10. How to merge the two meshes?

    Oh, that's even easier, just add them together.
  11. How to merge the two meshes?

    In this case you could probably get away with just ray'ing one of top of the other. For more complex setups/shapes you can use VDB's, but as I said, don't think it's necessary in this case. Edit: Oh, I just got to think about how you set this up, if these are just out of the ripple solver, you could probably just feed one solve into the next one, thus stacking the effect instead of solving one, then another and combining them.
  12. Particle collisions inside animated mesh

    I just thought it sounded like redoing something already in Houdini as that kind of setup would be "position based dynamics", so what the grain stuff does. If I understand it correctly. And about the grain solver being overkill for some setups, I imagined the sheets and solids deactivated the dry/wet sand solver parts, but I haven't really checked the underlying setup - I need to be in a particular mode to jump into the SESI setups as they have a tendency to break my mind slightly...
  13. How to tweak simulation parameters intuitively?

    Sliders. [firecracker....................................<->............................Birth of the known universe] To be honest, I think the idea of shelf tools as a starting point are very suiting for the type of application Houdini is - I really don't think Houdini will ever be easy or intuitive unless you get an enough grip on how the software ticks, then more and more things will start to make sense and a lot will start to feel pretty intuitive.
  14. Particle collisions inside animated mesh

    This is PBD, so there's really no need to recreate what is already in H14 using the grain solver. Or am I missing something?
  15. Geometry self collision.

    Looking forward to it.
  16. Hehe, man, either you changed your initial post or I just went on autopilot answering this one - shame on me. Shame. Shame. Pling. And I'll give you a hint about your issue - you've got a 50x50cm emitter. And though a modern nuclear weapon could probably be built that small, if you want proper behavior, you need to keep to proper scale - so try doing a 100x100 meter emitter and you'll start to get some way more reasonable results out of your sim.
  17. I recently did this setup for a KIZ music video... ...and I started out with the Side Effects nuclear bomb asset from Orbolt and just started tweaking until I had something looking what I was after - typically I ended up scaling it so the final shape was never seen, but that's often the case, hehe... The shockwave was another sim which I rendered from two angles and combined, also mirroring it and having a couple of different times versions and layered them up for the final look. You do what you gotta do when you don't have the time to setup, simulate and render huge scenes...
  18. Geometry self collision.

    You can use the PBD for this, the grain solver, so you'd animate with the mesh intersections and then add the grain solver on top and sim the collisions, this will give you volume preservation, etc...
  19. Flat Tank missing nodes

    Some format imports are just creating these insane nested node setups, probably something for the dev's to make a run for, at some point - or perhaps it's for reasons I don't get. And fbx isn't really that bad, try importing alembic, hehe... But I usually un-nest these imports as good as I can before setting things up.
  20. Honestly, I needed the flag blowing in the wind ...

    Try using the grain sheet, then just add some wind in DOP's, perhaps lower the gravity. Here's a plastic bag setup I did for a guy here a while back, more cloth/silklike than plasticy, but telling that this could work really well for a flag in the wind type setup.
  21. Particle Collision Problems

    In the solver for your collision object, you have the option to visualize the collision geometry, that will allow you to see if that is the problem or something else. As an example, I've done setups where I moved something at object level creating gaps without there actually being gaps in the simulation itself. And if the problem is the collision geometry, you have all the optins in there for correcting the creation of that to match your actual geometry better, among other things using convex hulls.
  22. If you want to keep the look/behavior of the setup but change color, always the shader. Messing with the DOP setup will of course change the behavior of the setup.
  23. Increasing Fracture Density Over Time?

    Ooh, awesome topic, Atom. For doing fracturing feedback loops, the workflow using volumebreaker in Thinking Particles is just genius - here's some RnD I did for a short last summer... And of course this must be possible to replicate in Houdini. The only question is, what way is the best/easiest way to do it. I'm thinking something like a SOP solver setup using the measure SOP and creating rules through filtering trough attribute values out of the sim for determining if/when/what fragments refracture in the DOP...
  24. Houdini Pyro : Nuclear Mushroom

    Unforgettably rude, Diego, I will immediatly unlink you at LinkedIn. LOL, to be honest, your post confused the sh!t out of me at first as I mistakenly clicked your link in my subscription mail as the one to bring me to this thread, but instead I came to your thread, a thread I didn't subscribe to - but was about the same thing. So I started scrolling but nothing matched up, I got seriously confused. So I took a bath and now it's all sorted. Seems Archimedes had all this figured out 2000 years ago. @Lionel Just to add something many miss - if you want to have a huge realistic explosion, you need to use the right metric for it, so match it up with the scale. If you haven't messed with it, the Houdini units are meters, so set it all up so your fireball gets into that 300-500 meter ballpark, and you'll have the correct ratios for air resistance, gravity, smoke viscocity and everything else the godlike mathematicians at SESI included in their equations, creating these gas solvers that are the foundation of the PyroFX system... You won't get big explosion dynamics in a sim that is mathematically 4 meters wide in the Houdini 3D space. And this is kinda weird if you come from FumeFX in Max as that system is build around tweaking your way to a realistic result without any real bother about scale or such, or as I heard Allan McKay say often in his FumeFX tuts, "I'm punching in numbers I know work." In Houdini the numbers you'll know works are the ones you are after. Keep to correct scale and you will get a lot of realistic behavior out of PyroFX, "for free", so to speak.
  25. Houdini Pyro : Nuclear Mushroom

    A tip, if you still have access to 3ds Max, install 3Delight for Max - free for one 8-core machine license - and then you can export your Houdini Pyro sim's as VDB's and use the 3Delight VDB import object and render your volumes way way faster than with Mantra. The mushroom cloud and the two shockwave sim's I did for the KIZ music video were all exported as VDB and rendered out of Max using 3Delight, I would guess 5x the speed compared to if I'd done it with Mantra. http://www.3delight.com/en/index.php?page=3DFMax_overview *** Edit: If you got Houdini FX you can use 3Delight right from withing Houdini, I run Houdini Indie so I have to run 3Delight through my old 3ds Max 2014 license...