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Everything posted by SquirkyTurtle

  1. Hello Houdini people Has anyone ever had funny results when emitting flip from cached geometry? I am having some object fly around my scene (they are just geometry instanced onto points). When emitting flip from them, it behaves weirdly, not like the same emission from the same objects (animated instead of simulated) is. I am wondering why this might be and if it has something to do with the velocity or maybe substeps. I tried adding more of the latter and adding a timeblend but it does not seem to fix it. I am grateful about any input!
  2. Emission from cached geo opposed to animated

    Alright, so I have figured out that the velocity is the problem. I tried to delete all velocity off the cache and recalculate it using a trail sop but for some reason it doesn't give me the same results as it does for the hand animated geometry. I get weird negative numbers and extreme high values for some points.
  3. Oh wow, thank you so much! This does the trick
  4. Hello people of Houdini! I am having a problem and I am struggling to find a solution. I simulated some points, they start of as a small number and accumulate over time. Now, I want each point to have a unique point number. Normally, when dealing with a changing point number, I create an ID attribute at frame one. But so far, I have only ever encountered scenarios where the points got less and less over time, not more and more. I am not sure how to approach this and it is driving me crazy. I don't really want to resimulate my points and turn off the spawning over time, but I need to keep track of which point is which. If someone has an answer to this issue, I am super grateful for any input. Thank you so much in advance!
  5. Yes, I could. It is a bit painful but defiantly an idea thank you!
  6. Hi, thank you! But I think you forgot to attach the link
  7. Viscous fluid trail

    Hello Houdini people I am trying to simulate a very viscous sticky fluid wrapping around and hanging from a sphere but never fully dropping of it. The sphere moves around and I want the fluid to pull trails but be stuck to the object. I am kind of struggling with the approach and was wondering if anyone had any input of any kind? I have tried advecting particles by smoke and killing them off quickly to cause the Illusion of a trail but its not really what I want. I also played with surface tension and just normal trails but I feel its not going anywhere. I'm happy and really grateful about input of any kind
  8. Houdini flip "sinks" within boundary layer

    Does anyone have an idea why my flip sinks within the boundary layer like you can see below? It started at the same level as the boundary but when I cache it and play it back it starts "sinking" until it randomly stops at one point and reflects of the sides towards the centre? I am grateful for any help
  9. Flip simulation static object collision problems

    I changed the velocity from particle to volume and that fixed it. I am still not sure why this is but at least I am not getting exploding flip anymore
  10. I am having a massive problem with my flip sim and I have no idea what causes it. Basically, my simulation is a simple fluid tank, with some static static objects and one deforming static object, that I cached from another simulation. This object is a "thick plane" shattering and cracking, being pre-fractured and dynamically fractured using a "voronoifractureconfigureobject" in the other simulation and then cached as a .bgeo. I have made a collision volume for this using "collsionsource" and the collision mode is volume sample. I changed the collision separation on the flipobject so I get correct collision guides. Now, when playing the simulation the fluid displays unnatural behaviour. It randomly "explodes" all over the place. I added a sopsolver in which I manually tried to clamp the velocity and even set it to zero but it just causes points to appear in random places. I took some flipbooks and images, you can see them below. I have no idea what causes this and I am getting very desperate to fix it so I am super grateful for any suggestions of any kind. The second image is the collsison guide on the static object, the first one is the collision visualisation. I also attached a bit of tbroken_flip.mp4broken_flip.mp4he flipbook showing whats happening (one is with the velocity set to zero inside the sop solver, the other one is unchanged velocity). Also: I have tried using an rbd object, an rbd fracture object and a rbd packed object instead and I get similar results. I also tried higher seperation, remeshing the object before it enters the simulation, adding a trail to compute velocity and setting the objects velocity to zero on SOP level. I am also using a narrow band but I get the same results if I turn it offf. My scene scale broken_flip.mp4broken_flip2.mp4
  11. Dynamically add rigid bodies to flip sim

    I have kind of solved this problem and I am now just loading in all the objects from frame 1 and changing their active attribute as the simulation goes along. To do this I need a SOP solver inside my DOP but I am not sure how to wire the rigid body solver, the flip solver and the SOP solver together? I need the SOP solver to only affect the rigid body object. I tried using a multisolver but all combinations I tried seem to be not working and give me funky results with the flip. Does anyone know how to do that the right way? Edit: Never mind, I figured it out I think. I am using a multisolver for rigid body solver and sop solver and then I am merging that with the flip solver. I am not sure why this was not working previously, I might have had the wrong relationship in my merge node or something
  12. Dynamically add rigid bodies to flip sim

    Hello there I am working on a flip/ rigid body setup where I basically have some packed objects gradually being added to the simulation. They are simulated in another DOP and cached out and I need to drop them into the fluid DOP at one point (they leave one simulation and enter the other), which means the amount of rigid bodies in DOP 2 will have to update at simulation time (the first frame there is none, then they pop up one after another). I have a SOP solver and I thought I could just merge and update the geometry in there, which works when it comes to the rigid bodies, but somehow they loose interaction with the flip? Does anyone have any suggestions on how to do this the right way? Thank you!
  13. Crowd agent orient problem

    Thank you so much, that was a great explanation, I am really grateful! I got it now and my clips blend nicely
  14. Hello there I am doing a crowd sim and my agents need to turn around quickly after a certain event triggered and run away. Now I have a clip for the turn but when it plays the agents heading vector doesn't actually turn so when I try to do the transition to the running clip (and new direction) afterwards, the agents flip back and then turn around. I tried to solve this by manually updating the vector right when the clip changes but I get a horrible blend between the clips and stuttering in the movement. I am wondering if anyone knows a way to approach an issue like this smarter? I have set up a transition graph but I can only blend between both clips facing one direction and I am not sure if there is a way I can change the clip orientation? I am grateful for all suggestions!
  15. Crowd agent orient problem

    Okay, I made a quick example file with what I am attempting to do. Basically, I would like the turn clip to play and then I would like to blend into the running clip once the agent is turned. I am pretty new to this so I am sure I am not understanding or doing something right. example.zip
  16. Crowd agent orient problem

    Will do when I'm back at my computer, thank you
  17. Crowd agent orient problem

    Alright, so I have set the turning clip to be locomotion and the heading now updates but as soon as it switches back to the running clip, he starts turning backwards again? This clip is not a locomotion, should it be?
  18. Crowd agent orient problem

    Yeah I have but it isn't updating the heading, should it do that while the agents is spinning around? Do I have to do any setting up for this? Oh and thank you for your reply Edit: I did not set up the Locomotion right, I am stupid. On it now.
  19. Helllo there in my sim, I am using a voronoifractureconfigureobject and my simulation runs perfectly fine and my object fractures nicely until I add a static ground object. All over sudden there is parts that do not fracture anymore and I don't understand why. I assumed it might be that the fracture limit gets met once they don't eternally fall but if I put it up to a super high number, I get the same result. Does anyone have an idea what I am doing wrong? I am grateful about any kind of help. Thank you in advance!
  20. Ragdolls explode

    Hello! I totally forgot to reply to this but the problem fixed itself when I redid the collision layer so I assume something broke there. Thank you so much for your help though
  21. Ragdolls explode

    When my ragdoll state is triggered, my agents mesh explodes and breaks in the simulation in very disturbing ways. When setting up my collision layers and testing it outside of the dopnet, it seems to work fine. Does anyone have an idea why this is and what I have done wrong. I am using FBXs, but when testing with the Mocap characters from Houdini, it works fine. Thank you very much in advance.
  22. Ragdolls explode

    Nothing, it is not displaying any guide geometry. That is weird, is there anything I missed setting it up? I built the collision layer and then I configured the joints, is there anything else I got to do?
  23. Ragdolls explode

    Hey thank you so much for reply. Yeah that's what I did and its fine. I'm not doing a partial ragdoll but I am not sure what a motor driven ragdoll is? I'm just trying to trigger the state. I've also tried to just set the ragdoll state to active in the normal walkstate (the walk is fine) but it always breaks.
  24. Crowd and Rigid Bodies

    Thank you so much! I can't believe I missed this
  25. Crowd and Rigid Bodies

    Hi there! I am trying to make my crowd interact with some rigids (have them walk into a box and make the box move on impact ect.) but the box is not actually moving. I made a collision layer but when I try and display it in the solver, there is nothing. It works in the example sideFX file (ragdoll one) and as far as I see, there are no differences. I would be super grateful if someone could give me a nodge into the right direction Thank you