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Found 163 results

  1. Hello, I have been trying to recreate the black hole effect from the film 'Eternals' for a few weeks now for a thesis project I am doing and I am not really getting close. This is the effect in question: Arishem's FInal Judgement The effect happens at 1:17 My approaches was to create some circles with an animation spinning around the circles driven by the curveu attribute and offset by the 'copynum' attribute I got from the copy and transform node. I was driving a smoke sim from this and then I used the curveu as a temperature attribute to drive some scattering in the pyro shader. However this approach has not really gotten me close. I realise its quite a complex effect but any tips on recreating it would be fantastic! Thank you for reading
  2. Hi I'm wondering how I would simulate large bubbles as they're forming or "being blown" I guess I'm mostly asking high level is it possible to create this geometry on the fly and also continuously add new constraints to it until it's fully formed, and then flies off on its own to interact with the world. Thanks
  3. Hello, I'm using Vellum Source to emit multiple spheres over time and I want to increase the Rest Length Scale of each individual sphere every frame, starting at 1 (for each piece) and incrementing. Realized I have no idea how to select individual bits of sourced geo within DOPs and can't seem to find it anywhere online. Thank you!!
  4. Could someone take a quick look at the example file? I cant get the nearpoint function to work. thanks nearpoint in dopnet.hiplc
  5. Need help simulating drifting snow

    Hi, I'm trying to simulate blowing snow, like in the video below, but am having a tough time. I'm emitting from scattered points with animated noise on pscale, density and velocity, and I'm advecting the sim with a velocity volume derived from a set of animated curves (to get the wavy motion of the snow). The problem is that the smoke disperses quickly and loses it shape, and I can't get any fine detail into the smoke however many gas disturb/turbulence settings I try (I'm using speed, derived from vel, as a control field). The pyro sim has no temperature field or buoyancy applied. In the reference the snow is fuzzy and keeps its shape throughout, and I'm stuck about how to achieve this. I've attached the .hip if you feel like taking a look. Thanks Blowing Snow Flipbook 2.mp4 Blowing Snow Ref.mp4 Blowing Snow Simulation 09-02.hip
  6. Animating a Spring Constraint

    I'm trying to get these two objects to move towards each other after they hit the ground. Blend solvers are being used to allow the objects to transition between their keyframed positions and dynamic states and I need to add an attractive force which is what the spring constraint is supposed to be for. If I plug it in and doing nothing to it outside of hooking up the constrained object and the goal object it works fine. However, I want to control the timing of it so it can work it into an animation. When I tried to keyframe the spring strength or activation parameters the constraint would stop working or not work properly. Result from keyframing the activation parameter. The objects do not pull towards each other, the constraint just keeps them in place. Node network Does anyone know why this is happening? Thanks in advance!
  7. OpenCL for pop?

    Is there an existing workflow to run a pop sim on the gpu?
  8. I'm having an issue with the Beach tank shelf tool when I try to use the Ocean Waves SOP (along with a couple of Ocean Spectrum SOPs) to seed the waves. As you can see in the video, the velocity of the waves seems to be transferred to the boundary layer of the simulation, but nowhere else, and the passing of the instanced waves seems to have little impact on the simulation, when the waves should in reality be breaking on the beach. I've already played around a lot with this and I believe it could have something to do with the velocities of the points on which the waves are being instanced, but I'm not sure. Any suggestions would be great, thanks! Beach Tank Issue.mp4
  9. Please someone help me with this: I made a Group in POP solver for collision of particles named 'hit'. Now in the wrangle node, I made a chramp for the velocity based on my own custom attribute which is '@customage' from 0-1. Now I want to ask that for POP attract, if I want to make the velocity affect all the particles except my 'hit' group particles, then how can I do that. Your help will be appreciated. Thanks! Particle attracting effect.hip
  10. Hi, I'm getting some very weird behaviour with some of my particles that collide with my VDB. They should come to rest but a small percentage don't ever stop moving. The collider is a VDB created using the Collision Source node and represents the original RBD pieces converted to a volume. I've tried using Auto Sleep and various other methods but these same particles just never stop. In one of the videos the purple colour is the active particles and the red are the sleeping particles. I've upped the substeps in the pop solver to 20 and they sill move. Any advice would be much appreciated. POPNeverStopsFlipbook.mp4 POPNeverStops.mp4
  11. wave-like information transfer

    I am building a flock using separation, cohesion, and alignment, but I'm modifying the alignment variable. Research showed that you can use a superfluid equation to define the speed of the turn information traveling through the flock, and that helps give the flock that really fluid look. I'm trying to figure out how to control the speed of the information. I need to 1. be able to dynamically change the speed of the information based on the flocks cohesion (when they're more cohesive, the information travels faster) 2. be able to send out "waves" of information every frame, so 24 times a second 3. send out non-disappating waves (I tried the ripple solver, but one of the problems was the dissipation of the magnitude of the wave) I'm thinking CHOPS might be the best bet, but right now I'm just finding a lot of CHOPS information dealing with sound and audio. LMK if anyone knows of a good node that could help me. Right now I'm looking into just hard-coding it in VEX (basically storing the velocity of ALL of the boids at 10 frame intervals), but that will be VERY intensive.
  12. Hello all, I'm looking to do some basic volume displacement using dual rest (something I've done before in the past), however I'm stumbling at the first hurdle now, when revisiting it a few years on: I cannot get a working rest_ratio and rest2_ratio out of a pyro sim. I could calculate it manually using the frame offset and blend length params, but I seem to remember simply being able to grab it from the solver. I have initialized the rest field in the smokeobject DOP, as well as dual rest mode in the pyrosolver advanced tab, however the ratio detail attributes don't appear to move. Looking inside the sim at the smokesolver_build2/record_sim_settings_to_initialization_data script I can see that the ratios are being correctly calculated, however this isn't being exported properly when I lay down a Dop Import Fields SOP. I've attached a really basic hip file. pyro_dual_rest_ratio_not_working.hip Can anyone help me? edit: using 18.5.633 Thanks in advance.
  13. I have an alembic with a lovely bit of movement happening, lying down on a ground plane. I'd like to make parts of it floppy, which I can do with vellum and a pin to target with an attribute that scales the pin stiffness so it's lower on the floppier parts. No problem there. The part I'm not able to figure out is this: I actually want to hang this up by one of the floppy bits, but still be able to use the shivering/shuddering from the target animation. The target animation is apparently evaluated as absolute coordinates, rather than deltas of a rest mesh, so even with the floppy part being hung up, the pinned parts are still lying on the "ground"/seeking the actual point locations of the target. Is there a way where I can get it to evaluate the target so that even if some of the animated bits drift (and move some of the not-quite-100%-pinned areas) the vellum will incorporate the source object's animation, but at it's new simulated place? Thanks for any help!
  14. Free video tutorial can be watched at any of these websites: Fendra Fx Vimeo Side Fx Project file can be purchased at Gumroad here: https://gumroad.com/davidtorno?sort=newest
  15. Deforming texture maps in Dops

    Would the deformation of texture maps work DOP networks?
  16. Hi Doing a vellum coiled cable sim and while I'm happy with the feel of it I've noticed I have some spinning close to pinned points, instead of bending. Is there a way to avoid this? Video shows the sweeped curve and then it shows the group used as pinned. phone_coil_cable_spin.mp4 I've noticed that vellum does not transform the input geo attributes (am I missing something?) so instead I used a point deform to preserve the sweep's orientation. Works well for most of the curve but not great on the tips. All constrains are super stiff so the coil shape can be maintained, so this could be the cause of the geo not bending but twisting. Still I wasn't expecting that twist. The Settings I'm using on Constrain and the Solver are below. Let me know if there's something to consider to avoid this behavior or to have Vellum transform input attributes. Thanks.
  17. Free video tutorial can be watched at any of these websites: Fendra Fx Vimeo SideFx Project file can be purchased at Gumroad here: https://gumroad.com/davidtorno?sort=newest
  18. I have a basic dops ( vellum to be specific) and i want to add elements dynamically to the sim. in the example > case1 , i create an random line and add it as a vellum hair into the sim .. and this seems to work. case2 and case3: i want to access the current frame of The Dops sim, and i create a line from a fixed point to a point on the mesh( think lightening ) .. but doesnt work. cant seem to access the current mesh and create a line(s) and adding it back to the sim.. any tips and pointers would be appreciated. thanks sideFx.hipnc
  19. Geo appearing twice in Dops

    hi guys, I have a vellum balloon constraint on my geo. Until there, everything working ok when I press play. I have added an Attach To Geo Constraint inside the dopnet and now, my geo is doubling up when I simulate. One of them behaves with the added constraint and the other one without. Whats wring? Tx
  20. Vellum Pressure

    Hi, I wanted to ask about some of the hidden intricacies of vellum pressure. In particular I recently found out about the @pressuregradient attribute that determines the direction in which the object expands as pressure is applied. I wonder: How is it determined? I suspect something to do with Normals, but then when I visualise the attribute it tends to always have a rough relationship with {0,0,0} - why? This leads to strange inflation especially if an object is off-center and then it trends away from the origin, as opposed to away from its center of mass... Can it be manipulated in the solver? It would be nice to procedurally predetermine the inflate direction, although I'm not sure how to access or manipulate this attribute. Can it be manipulated per frame? If I have multiple objects that start in a rest position and their inflations happen one after another - one ball moves other balls out of rest position for example... Then once the ball that has already been moved starts to inflate, is it computing on the pressure attribute given at the start of the solve, or the one at it's current frame number? I could probably word these questions better and I do apologise, but at the moment it seems I have run out of places/videos to read/listen to. Thanks a lot for your help! Cheers.
  21. Hi. I am trying to make a simple HDA which will drop down an asset on another asset. It works fine inside Houdini but it doesn't work in UE4 or Max. What is wrong with current setup? drop_dop.hda
  22. Wire constraint network Question

    Hi all- Building a procedural constraint network for wires by connecting the interior points in a grid. It works fine for some grid dimensions, but not others, where the sim blows up. shown below a 5x5 and a 6x6 grid. A 15x15 grid will work fine, but a 6x6 one won't. Curious! I'm building zero-length constraints from the interior points and setting the anchor points as follows: int wirepts[] = nearpoints(1,@P,.0001); foreach (int wpt; wirepts) { if(wpt != wirepts[0]) { int pt1 = addpoint(0,v@P); int pt2 = addpoint(0,v@P); setpointattrib(0,"anchor_id",pt1,wirepts[0]); setpointattrib(0,"anchor_id",pt2,wpt); int newprim = addprim(0,"polyline",pt1,pt2); setprimattrib(0,"constraint_name",newprim, "WireGlue"); setprimattrib(0,"constraint_type",newprim, "position"); } } setpointgroup(0,"delete",@ptnum,1,"set"); I delete the original points later - I'm not using the first of the nearpoints to avoid a prim with the same anchor points, I thought that might be the problem, but it didn't seem to matter. Does anybody know the reason why this happens? Am I missing something? Thanks - I'm including a sample file. wireGridConstraints.hiplc
  23. Grouping DOP objects by Impact?

    Hi, First time posting here and relatively new to Houdini, so please forgive any poor use of terminology etc. Basically I want to group DOP objects, specifically RBD pieces, when they are impacted by another object. I want to do this so I can add gravity to each piece as they are impacted. When I look at the geometry spreadsheet I can see the Impacts data appear, but I don't know how to then group these objects by this. If it helps to visualize what I mean, I've made this puzzle globe made of 500+ pieces, and I'm throwing this ball at it to break it apart. I've got my sim working well enough, but currently gravity is not acting on any of the pieces, so when the ball hits, it's breaking the pieces apart but they are acting as if in zero gravity. So now I want to group this pieces as they become impacted either by the ball, or the pieces next to it, so hopefully by the ends all of the ball collapses. Thanks for any help, Alex
  24. Vellum Collision Problems

    Hello! I am trying to deepen my understansing of vellum by building the solver netowork myself. I have hit is very enfuriating sustuation were my character litterally walks out of her pants. When I use the sop based solver this dosn't happen. I am sure I am missing something but it seems most things I have tried are giving me the same result. I am using an almebic cache for the collider, and cloth geometry brought in from Marvelios Designer. I am using an collision source node to generate a vdb for collisions, and using a staticObject set to “Use Volume Collision” and “Volume Sample” for division Method. Here is what I am getting
  25. I'm trying to create a Python UI state that returns the currents fields in a DOP network. I want to query the fields and then store there values so that I can print it in the viewport. I can find all the python documentation to get the fields themselves, but I can't seem to find out how to get the values stored in the voxels. I know it can be done in SOPs, but I really want to do it directly in DOPs. Is this possible? FYI, just using a simple Sparse Pyro Shelf tool for my testing. I want to query the density and temperature fields and calculate the maximum value stored in those fields. Thanks!
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