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Found 38 results

  1. I have a popnet creating some particles with the POP spin, to have a random rotation in each particle, also Im copying a tube in each particle, the tube rotates as it supposed to, but when they hit the ground, the tubes stays with a random rotation as well instead of pointing Y. I'm thinking that if I use the normals instead of the POP spin I could blend between the N0 and N1 when the particle hit the ground, using the hit info from the POPnet, but truthfully I don't know how to achieve this .-. I'm using POPs and copy the tubes/coins to the particles because the particles born magicaly from the floor after a character hit the floor with his cane. If anyone could help me or have any idea I would appreciate it!!!
  2. I have a popnet creating some particles with the POP spin, to have a random rotation in each particle, also Im copying a tube in each particle, the tube rotates as it supposed to, but when they hit the ground, the tubes stays with a random rotation as well instead of pointing Y. I'm thinking that if I use the normals instead of the POP spin I could blend between the N0 and N1 when the particle hit the ground, using the hit info from the POPnet, but truthfully I don't know how to achieve this .-. I'm using POPs and copy the tubes/coins to the particles because the particles born magicaly from the floor after a character hit the floor with his cane. If anyone could help me or have any idea I would appreciate it!!!
  3. Hi! This is me trying to understand the popSolver in houdini. What is the difference between this two inputs and why they are both wired like that by the shelf (Check the attached image) The particles seems to do the same thing if I rewired as I showed in the second network and they don't do anything at all with the 3rd one. Also why is the wire dotted between the popsource and the popstream, They only work together is both inputs (pre and post) are wired like that. Thanks and pardon my English :$
  4. Hello! I'm trying to kill points inside DOPs (well a popnet actually). The way I'd like to do this is by finding the closest point to the ground object (how do I reference an object in DOPs?) and computing the vector from the POP point to the nearest point, then dotting that onto the ground points normal vector. That's a nice way to figure out which side of the ground the point is on, then killing it. At least that works outside of DOPs. I'm wondering how I can do this inside DOPs because I don't want to post-process kill thousands of points if I can kill them in the simulation. Any ideas? Thanks, cw
  5. Hey all I'm quite new to houdini so please bare with me. Is there a way to use an audio output from chops to change the position of a particles? Can I do that by using a pop vop? If so, how can I import my chops output in there and add it to the position of my particles? Is there maybe a better solution for that? Thank you!
  6. Hi everyone, I'm trying to use the points created by a particle sim, and copy lines to them, then solve them as wires. However, so far I can get nothing to work at all. Nothing ever shows up the in viewport, I don't know why. I have tried using one dop network to create the particles, and another to solve the wires, but this doesn't work. I suspect it's something to do with the fact that the newly created geometry needs to be imported into the DOP network, but I do not know how to do this. Any advice would really be appreciated. Wires_on_Particles.hipnc
  7. Hi all, I am trying to use geometry to control attributes on particles. Would anyone know how to do that? Problem. I have a flat bed of sand grains with their "static Kinetic" set very high. But I would like the collision geometry (a hand in this case) to diminish the "static Kinetic" attribute to a very low setting. Much like using the sop solver for fluids. Cheers, dreamagery
  8. Hey guys! Not really been active here, but planning on changing that I've ran into a little issue and i'm not sure why it isn't working, so I thought I'd try to ask on here. I have some particles following a curve using popcurveforce. I want to be able to influence the thickness of the radius so I made a maxradius attribute on my curve which i'm ramping. I was assuming it would pick up on the attribute but it doesn't. Anybody know? I've attached a HIP file. Cheers! maxradius.hipnc
  9. I'm trying to find a way to get bring in the velocity from a field i created in sops into pops directly. I can do this easily in dops with a sop geo and a particlestofield node, but i can't seem to replicate this in pops. I've seen this done before in a pop wrangle, but I don't know the code myself. Can anybody help me out?
  10. I thought I was losing my mind when I first ran into this because I thought I was just having a brain fart. But, When using the "Voronoi Fracture Configure Object" I can't seem to only have particles emit from the newly created inner surfaces. I attached my scene file to this post. I know that if I do the fracturing (non-dynamic) in SOPs, I get the inside and outside group. I feel like this is something that is super obvious and I'm just not seeing it right in front of my face. Any help would be much appreciated! Thanks!
  11. This has been a very hard search to find an answer to. What I'm trying to do is add an initial spin/rotation to a DOP object. I attached a simple scene of a torus that has an initial upward velocity and then just falls to the ground due to gravity. Essentially, I'm trying to give it a "punch" that will cause it to spin - but not perpetually. A good example would be if you had an object that hit "glass." Although the sim would be physically correct, to add interest it would be nice to add a little spin force to the shards of glass on the initial impact. I can't for the life of me find a way to do this in DOPs. I'm sure I could be overlooking the most obvious parameter, but it's also Houdini and sometime the simplest task takes some finagling. Any help is appreciated! DOP_spin.hipnc
  12. Hello I have a cube and a sphere. Sphere is the source for the particles. I also scattered lots of points on the cube. I want particles to go from sphere to points scattered on the cube, but I can't figure out how to import scattered points position as a target attribute for the particles. And then use @v = @target - @P Any help please?
  13. Hi, Silly question, but I'm using "old pops" and I just want to simply emit some particles when a point dies(not using collisions) and then create a small burst around the death event of each point dying. Any help would be appreciated as I'm a total noob with expressions/wrangles etc.
  14. Hello, I'm trying to convert a bunch of RBD objects in my case a bunch of cubes of a dancing person that has shattered to the ground into particles. I've tried using a for loop SOP and using a fuse node to get a single point and then using a copy SOP but the rotation is off and isn't identical. My plan is to the have the dancer reform using POPs afterwards. While i'm at it I might as well. My dancer is converted into points with a volume to points SOP but as it;s deforming the points are recreated each frame. My solution and its a pretty shit one was to use a point deform of the point converted dancer and apply the deformation there. Problem is obviously that the cubes no longer stay apart and depending on how radical the dancer is the more the cubes intersect. Is there anyway I can still keep them apart but not create new points for each frame so that when they are converted to RBD they don;t flip out?
  15. Hello everyone ! Does someone know how to use an animated mesh for driving some velocities of particles ? I have done a sim that I like but I want it to follow the character's animation... The particles born in the chest and goes to his head which is rotating... I'm pretty new to pops, I think that maybe I can make it move through a pcopen but maybe it is a bit too much for what I want to do ? Also, I'm not pretty sure about how to make it... Maybe it's possible to feed the pcopen with a scatter of point on the surface of the character ? Thanks a lot and have a great day ! (Once finished and online I will try to post it as a comment !)
  16. Hey guys, So i am attempting an attraction and formation effect once again, but stuck in between. So let me get this started, Suppose there are certain points scattered on a plane surface and they all have same facing direction. Now they need to attract to a target object and lock to the position and deform according to the movement of target object. They should orient according to the normals of the target object and should slide over the surface of the object as soon as they reach near to the target. I have scattered same number of points on the surface and target objects in order to match perfectly and am able to drive those particles towards the target object and lock them onto their respective ids. But the thing is i am not able to slide over the surface according to orientation of target object and not able to blend the orientation. As soon as i add pop spin or torque my orientation goes for a toss as it doesnt match to the target objects orientation. So i need to blend the orientation when they are near to their target ids and when they are finding it. Then i need to drive these as rigid bodies so that they do not penetrate when they stick to their targets so thats another issue. So there are couple of issues i am stuck with and need to sort out one by one. If someone could help me with this it would be great, I will try and post a hip file meanwhile if i can.
  17. Hey guys I'm currently playing around with Houdini so please excuse any silly questions. At the moment I'm trying to figure out if I can cull/delete any particles that aren't bound by constraints in my sand solver test. The setup is pretty basic but those pesky particles that fall off like debris aren't what I was trying to achieve; I kinda just wanted it to split into two separate pieces. Not sure how to approach it, but will try to read around it and figure it out. Any help would be amazing though! Thanks in advance
  18. I have a large particle cache and I am trying to delete any particle that passes through an object. I am currently trying to use a solver and I can't seem to get it to work. Sadly I can't upload a file. Any help would be awesome.
  19. Hello, I'm new to Houdini. I am trying to get particles to follow a curve and end up filling a bottle but I cannot get the bottle to fill or the curve to work effectively. I've tried a bunch of different things but the closest I've gotten is with these two files. I used an OBJ of a bottle and turned it into a VDB. In the first file (particle_flow_v07) I used a popnet to get particles along with a popcurveforce to flow along a curve into the bottle. It looks like it worked ok but the bottle doesn't fill up all the way. I thought it was because they are particles and not flip particles but was unsure how to convert them to flip particles. In the second file (v13) I tried using a sphere as a flip fluid emitter instead. The particles follow the curve ok, some of them fly off the curve even though I increased the force of it; and the particles that end up in the bottle only fill it to a certain point then they just spill out everywhere. I tried modeling a funnel to get more particles in the bottle but it didnt seem to work. in v13 theres also a torus I was going to try to use as a sink object but I couldnt get it to work correctly. Any help or advice would be very appreciated. EDIT: So I tried a bunch of tests and I still get the strange purple collision box through my ground plane; not to sure what that is; maybe its the particles colliding with the ground plane? The particles flow along the curve beautifully so thank you for the tip about my particle separation. Particles are still leaking though my geometry and I have a bad feeling it's because of the obj I found online but I am still unsure. particle_flow_v13.hipnc Glass Bottle.obj particle_flow_v07.hipnc
  20. Ok, so this is about me (and anyone else interested) learning how to manage particles in groups/streams and I'm going back to the type of growth I've done before, stacking POPs, but never managed to get working in one single POP network. Basically, the groups and/or streams just don't act as I expect them too, I just don't "get it", how the streams/groups are handled through the solver cycle... So this is what I came up with, because if I understand how to set this up, I know I "got it" - so to speak. Here's the "rules". Blue particles are born from the orange input point on the first frame. Blue particles create a trail of red, static particles. At a random interval, blue particles replicate a pink particle. Pink particles create a trail of green, static particles. Pink and blue particles avoid the static red and green particles. Pink and blue particles also travel through a noise field. The noise doesn't affect the red and green particles. Oh, and the colors aren't just descriptive, they should have these colors. And it all seems so simple - if I still was in Max, I'd be able to set this up in PF or TP in 10 minutes - but getting this going in a single POP, I can't even get half way before it "breaks", thus the very basic hip file. No reason to supply the 15 ways I failed to do this... splittage.hipnc
  21. This roadblock stemmed from this thread that was started here. I thought, wow, this is awesome, you can do so much - such as fracturing. However, when I tried to just do a very quick "let's see if this works" setup in my DOP network by adding a Voronoi Fracture node; it ignored it. <~This was using a Packed Rigid Body Object (I've attached my scene file without the voronoi node). However, when I switched the Packed Rigid Body out with a Standard Rigid Body object, it fractured. I've been trying different methods to the best of my new abilities to get this to fracture, but I can't find an answer or figure it out. I took Matt Estela's setup from his site posting here and tore it down to it's barest of bones. In short, I'm trying to get the spheres to fracture on impact using the packed rigid bodies that are emitted from the POP Source. Blah, this forum is the best. Thanks for any help you can give. fracture_test.hipnc
  22. I'm trying to figure out a way to take 2 objects in a merge and then randomly output 1 or the other to a CopySop. Simply, I have the copy connected to particles and I just want the shapes to randomly go to a random particle. Right now(for obvious reasons) it's just taking the 2 merged objects and assigning both of them to each point. I attached my file and left a blue sticky under the green nodes where the issue is taking place. I do have questions regarding this problem. - I know I can merge multiple objects and then in the DOP node that has those particles, just use packed geometry to achieve this. - Is it even possibly to do what I'm trying to acheive in the way I'm trying to in my example file? - Which method is best? - if one is better than the other? Many thanks in advance! I'm always unsure if I'm being super confusing, so I apologize if I am. dop_crack_part.hipnc
  23. dops

    I'm new to Houdini but I know that when version 13 came out, POPS AND DOPS were merged into Dynamics. For the life of me, I can't figure out how to make particles into geo shapes. I'm not trying to create POP Particles that are then converted into proper rigid bodies. I'm literally just trying to take the POP Particles and add a shape to them. So yes, there will be intersections between the particle shape and collision geo. I attached my file. I could get the particle to be wrapped/meshed as spheres if I did use a copy sop on both a sphere and a POP setup. But trying to have those particles collide with other geo wasn't working. If I'm being confusing - in the most basic form, I just want the colliding particles to be meshed as a sphere. Those spheres don't need to be collision accurate, they just need to wrap the particles. Thank you so much for any help! Best, Michael POP_SHAPES.hipnc
  24. Hey guys, first post here. I'm extremely noob at Houdini and I've got a very basic question. I've got a particle system going, and after the POPs system in the Source Particles SOP it creates, I'm trying to use the Y position of each particle to drive a Blend Sequence that is copied onto the particles with a Copy SOP. What I haven't been able to find is how to query the Y position of my particles. I can find their positions with the Geometry Spreadsheet, but the name of the attribute it gives me is "P[y]", and typing that into an expression doesn't seem to work. I had thought it might be "@P.y" but that errors out as well. I think one of the problems is that I'm not telling Houdini WHAT to find the Y position of. But again, not sure how to find that. I've googled and did a cursory search of the forums here but all the posts I've found are way more advanced than this simple thing I'm trying to find Can you fine gentlemen/ladies point me in the right direction to find how to query this sort of basic data? wk2_copy.hipnc
  25. I'm new to Houdini, transitioning from Max(TP, pflow, Magma...etc.). I started by messing around probably how everyone else did by using the shelf tools. However, I'm now trying to really dive into it using the application as it is intended. I figured that I would start off with a very straightforward and simple example from scratch - NO SHELF TOOLS. What I did first was actually create what I intended to make using the shelf tools first and then see what was going on and then start from scratch. In my example I just want to Have a Torus fall and have particles emit off the surface as it falls. The Rigid Body part is working perfectly, but the POP part of it is where I'm having problems. As soon as I add POPS into the mix (even if I make a different DOP network) I keep running into the problem that the particles seem to emit from a "ghost" of the torus geometry. One thing I noticed and can't seem to find an answer for are these 3 things. When I use the shelf tool to emit particles from the surface, it fills in information into the "DOP Import" Node that it creates. The information is created in the Object Mask of the node. I can't seem to find what an Object Mask actually does (I'll revisit this later). The shelf tool creates a SOP node with a DOP I/O and I don't know why. When using the shelf tools to make this setup, I noticed that If I deleted the information that was in the Object Mask of the DOP Import node at the end of the tree, the particles in the DOP Network wouldn't work at all. To revisit, what I was saying previously - I don't know what an Object Mask does/is for, and the information that was added when using the shelf tool route looked incredibly arbitrary to me. I included some images of my basic setup. Here is the top level Object view: You can see what I'm talking about where the torus falls, but the particles are emitting from the "Ghost" geo. This is where I suspect something is wrong, If I had to guess, the Object Mask has something to do with saying to use the geometry but not interfere because it's a mask? (I have the DOP Import node set to Bypass so that everything would show up.) And lastly, here is my DOP tree. When I select the Torus SOP this is what happens. But with the shelf tools, it used info in the Object Mask as the SOP Path. I know this is super detailed for such a simple setup, but I'm trying to understand what I'm doing and also what/why Houdini is what it is. Any and all help is much appreciated as I've been looking for an explanation to this for well over a week. I look forward to having that moment when it all clicks. Thanks! -Stark