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Found 226 results

  1. Particles opacity control

    Hello, I have finished a particle simulation using popnet inside SOP in houdini 15. I have added color and opacity information using POP color node. While rendering using mantra renderer, the color is rendered fine, but as alpha, it doesn't render what I created using POPcolor. It's all visible/opaque 100%. I want to control opacity. I have not assigned any shader yet. Please share a solution. Thanks
  2. I would like to ask some shading advices to render the same type of particles system like the one see in Black Panther credits. Is it geo instancing with low polygone objects ? how can we manage the glossiness variation on the particles ? Any tips to create the same result with Redshift would be awesome. Thanks Julien
  3. particles creating objects

    hey all! I'm starting to think on how to replicate an effect like this one attached. I'm starting to think about particles attracted by an object, and when particles are close enough or hit the object they inject opacity into the mesh and reveal the object itself. In houdini I'm starting with a simple POP attractor, but I'm having some back and forth elastic effect with particles (I supposed that is due to the pop force node that is keeping particles moving...). So what I'm trying to do is something that is snapping particles to their goal once they are close enough, and also how can I tell to the particles to get the color of their goal from the beginning, and how to kill them when they are close to the goal, and also how can I transfer the hit information to the mesh so I can make it appear...so many questions! thanks to anyone who can drop an idea! attractor_v001.hiplc SAMSUNG Pixel_1.mp4 SAMSUNG Pixel_2.mp4
  4. Hello everyone, I'm starting with Houdini and Python and I have a doubt which would influence my learning curve significantly. I'd like to know if someone has specific information about reaching the transformation matrix of particles in Houdini - preferably in Python. From the SideFx Python Documentation says it's not yet implemented. I also read somewhere here that it's possible through VOP/VEX. The objective is to make a particle export script from Houdini to Octane's CSV - to adapt Houdini to an existing workflow. This CSV file only has these particle's transform matrix. And it would have to be usable, for example, for 5 million particles. Does anyone has any tips? Or in alternative if someone has this script already, it would be great! I'm not a coder (MaxScript only) and it will take me ages to get it done... Thanks in advance! M
  5. Delete Mesh based on Particle Velocity

    Im having trouble with the delete by expression. I have a mesh which is wet sand, however i want it to start as the solid mesh and convert into the particles when they get awaken by the collision geometry. What would be the best way to achieve this?
  6. spray particles acting weird

    Hi, In my flip sim, I used the white water shelf tool to add foam, spray, and bubbles to my sim. The foam and the bubbles are functioning as I would expect, but the spray has strange behavior. It seems to be confused to as to whether or not a particle should be foam or spray. This results in spray particles getting stuck and not moving for a bit. When the particles become spray, they go from white to green. The faulty particles go from white to green, then back to white and back to green. It looks like they pile up against the floor (starting around frame 30), as show in the photo. I saw that someone had the same problem here: https://www.sidefx.com/forum/topic/45041/?page=1#post-201381 The fix the guy posted at the bottom did not work for me. Does anyone have any other ideas? Thanks spray.hipnc
  7. Hi all I am trying to simulate rain splashing on an already full tea cup, like the reference below. I have done a FLIP simulation which fills up the teacup quickly using an emitter inside the teacup, i have also done a basic rain simulation using the POP solver. BUT. i cant get the two to interact, the rain needs to be splashing the water as it hits it but i have been struggling for a few days and just cant seem to get it to work. I'm guessing its because i have used a FLIP solver for one and a POP solver for the other, but i have tried making them both FLIP or both POP but i just cant seem to get it to work with either. I don't know a huge amount about particle simulations so i might be being really dumb here but can anyone give me any advice or spot anywhere where i have gone wrong? I've attached the scene file and the geometry .obj that needs reading in, along with some screenshots of my nodes. Any advice would be amazing! Thank you in advance! rain_issues.hipnc teaCupV3.obj
  8. POP Flock Orientation issue

    Hello node friends! I'm diving in flocks.. I can't find any source of material to learn this besides a super old tutorial from cmiVFX. I was looking to create a bird flock, so far so good. Scatter a bunch of points, create a curl vel force and add a pop flock. The struggle I'm having has to do with point orientation, I can't seem to orientate the particles according to the direction they are facing, and since this is a simple bird animation, I can't find a way to make them behave properly. Does anyone know a good workflow for this? Pops or crowds? Have a good one!
  9. Hey everybody, I'm following some lessons about the reworked ocean tools in Houdini 16, and made a typical FLIP sim of a boat on ocean. But when I plug my compressed flip cache into the Particle Fluid Surface node and select "compressed fluid surface", I don't get any surface mesh at all - just the particles from the cache. Has this happened to anybody else or does anybody know how to get it work.
  10. Floating Particles in Water?

    Hi there! I am currently a vfx student and very new to houdini! So far it's been tons of fun but I've come across a problem, basically I want to create particles like algae and dust floating in water, but I'm really unsure what the best way to go about it is. Originally I was just going to do a very basic particle sim with some currents going through...but that didn't really work out. So, how do I approach this? Any little bit of help would be greatly appreciated!
  11. emit particles from pyro sim

    hey! I'd like to emit particles from a pyro sim, sort of a embers effect, so basically emit from areas where temperature is higher than a specific treshold. I'm using a volume VOP to bind the temperature, then a compare and a switch to use 0 where temperature is lower than and 1 where temperature is higher than the treshold. Now I don't really know hot to use this information to emit particles...I tried to map that on the density and maybe convert to a surface but no luck so far...
  12. transfer Cd to vdb from particles

    I wondering if this is even possible? I'm animating points through a solver and then turning them into vdb's. I want to apply a random color on each particle. Everything seams to work until I convert to polygons. I tried to apply an attribute transfer after the convert but as you can see in the attached image the scale is off? If anyone can provide further assistance... It would be greatly appreciated! (I also attached a reduced file since I cannot send the actual scene) Thanks, vdb_HelpMe.01.hip
  13. Hi! Houdini beginner here, I am trying to make a basic rain sim of rain interacting with an object and splashing on the ground making puddles. I am having a problem with the particles splashing on the ground, they are acknowledging that the ground is there but 50% of the particles splash against it but the rest go through it and splash just under it, i have tried using different things for the ground like a groundplane and geo but i keep getting the same problem. Any suggestions or help would be amazing! I Have attached the scene file if anyone would be amazing enough to have a quick look? Thank you in advance! Rain_001.hipnc
  14. So I'm trying to do this http://mos.3dworldmag.com/TDW229-pluralsight.zip <- Tutorial. Basically it's a "simple" teleportation/transmog of an object using particles. I've made it about halfway through but since they changed the materials from SHOPs I've hit a wall. The material nodes make my brain completely fry and compared to the SHOP stuff I can't seem to match it up ( I'm assuming you can ). I'll include my Hip file below for you to see where I'm at. Thanks in advance for any and all advice ! Teleportation.hip
  15. Bottle pour into glass.

    Beginner houdini user here. Trying to learn small scale simulations has been a struggle so far. It's been far from a logical journey so far i must say. The simulation i am working on is a bottle of beer poured into a glass and then the bottle is set down on again. With lots of iterations i have managed to get the first state of the pour to a good look i think. however i know want to set the bottle down again and that is when things start to get funky. The flip particles seems to increase in velocity when moving the bottle back and down again, resulting in them spraying out in control upwards. I have no idea what is going on and why, been trying different settings for quite some time now so if someone has a pointer in the right direction that would be awesome! Attaching a compressed scene file with all the geo and also a flipbook of it. beerpour.rar beerpour_v008.mov
  16. Solver on scattered points

    Hi All! I think this is my first post, so thank you for all the info shared here - I have a sphere with scattered points (in texture space) and a map that makes propagation of the points over the sphere. - I have a solver moving this points over the sphere. The problem is that the solver just move the points generated in the first frame and I want the solver to be acting over the points created over the frames. I assume this can be a stupid question Thanks in advanced! Domingo.
  17. I want to spawn some particles (rendered as sprites) and have their entire quad drawn every time -- even if it the quad is intersecting with other scene geometry! Is this possible? I have done this in OpenGL where I just disable depth testing before I draw my particle system but I couldn't find any option like that in either the POP nodes or the shaders. One terrible option would be to render every frame twice, once with the scene geometry disabled and one with the particles disabled and then composite them on top of each other... but that can't be the correct answer. I want to do this because I am trying to recreate the kirakira filter on iOS which overlays the image with jumbo starburst sprites to simulate a combination of glints and diffraction spikes hitting a lens. intersecting_sprites
  18. Saliva FX

    Good evening my fellow Houdini magicians. I have been trying the last couple of nights to create a Saliva Fx for a dragon roar but my brain is completely drawing a blank... So I figured I would try my luck here and see if someone is up for the challenge. any amount of help is appreciated to get me started. I have tested a few things, but I was not happy at all with any of it, so I am leaving a clean canvas here and hoping someone has a good approach to this that can get me going. in my head the saliva would be sticking to the teeth and then slowly get pealed off as the dragon roars, HOWEVER I am not married to a certain look of the FX, I just want to learn how to do a cool saliva FX. I have attached a clean scene file to start from and also the .bgeo sequence in case you cannot see the geometry in the scene from the locked node. Thank you in advance for all your help. Cheers. dragon_head.hiplc Dragon_head.rar
  19. LearnSquared Houdini Particles

    We just released a 4-part particle series I did for LearnSquared: https://www.learnsquared.com/courses/houdini-particles We cover everything from building our own particle solver from scratch, using the built-in Houdini particle POPS, showing how to choreograph and art-direct particle motion, and working through various rendering and instancing strategies.
  20. Hey magicians, I'm learning about velocities on particles, I made a shape that drives the velocity, but the particles are going diagonal instead of straight (the actual shape animation is just a vertical movement). I can't figure out whats driving this, I don't have any forces, any help will be great. Hip attached Thanks! particles.hip
  21. Hello! I'm having a bit of dilemma here... Currently I have a setup in which I'm emitting particles from selected points on my mesh that drive the pyro sim. I'm using the source from points option to do this. It works but I'm lacking control of the velocity. Currently, I'm working on a group of points via the bindGroup option on the attribvop and altering the normal inside the vop. Nevertheless, is this a good way to do this or is there a better method to have particles emit from the gills to drive the pyro sim. Really could use some help on this... thanx!
  22. Particles along surface

    Greetings to the best forum on the web I am struggling a little with wrapping my head around the xyzdist() and primuv() functions in vex. I have attached a scene file that holds a dopnet with some points created on frame 1. I would like those points to stick to the geometry coming into the second input on the dopnet. any suggestions to how this could be done is appreciated. I am in particular interested in the usage of the xyzdist() and primuv() solution, however other methods is also encouraged! should there be some people that wanted to "show off" a little vop magic that is cool too. looking to learn so hit me with everything you got. All in all a simple task but good fun. Thanks for playing Cheers particles_on surface.hiplc
  23. Hi Everyone, I am still new to houdini and I frequently run into the following problem. WhenI use VDB volume for collisions in houdini Particle or Flip sim, particles collide with the bound of VDB volume instead of actual VDB shape. It kind of creates a boundary around VDB and uses that boundary for collision. Its visible in the viewport in orange color (yellow color in the provided SS as d object was selected when took SS). I often get this issue and I dont know what I am doing wrong and how to solve it. Even If I use shelf tool the problem still persists. If anyone of you have ran into this problem then please let me know how u solved it. thank you for your time. Cheers!!!

    Hello, I AM DYSLEXIC - a very nice student project I worked on back in 2015 just got published, I did FX for it, all in Houdini, then handed over caches to lighting and rendering guys (rendered in Mental Ray in Maya). I really like visual style and it was really interesting to do some effects for this style of animation. Enjoy Short breakdown: 00:48 - paper (cloth) sim, a proxy collision geo of hero character was animated and used for interactions 03:22 - RBD simulation advected by hand-drawn guide curves and underlying FLIP simulation, some VDB meshes for hill filling, procedurally generated pages between books with fake dynamics (even though they got totally lost in the renders)
  25. Add custom force to foam particles

    Hi all, Anybody know how to add custom force to foam? I try use popvop but it don't work. I check witewater solver, its looks like force always 0 when particles is foam. Thanks!