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Found 77 results

  1. Hey guys, sorry for my english There is a way in Houdini to detect the collision and have a organic style deformation without dynamics to avoid the intersection of the meshes? I have some geometry groups (tentacles based on curves) in a single object, so, I thinks is possible with volumes and a vex expression with if and else, but I'm not so good with vex, i'm still learning. So, using a foreach loop , maybe converting the mesh into volumes and use a scatter to have the surface and inside points to detect their position, how can I import in a wrangle the groups and their points info to create this type of action? I know the message but i don't know how to write it, some ideas? Thank you
  2. Hey. I have a problem with overwriting values from wire object in SOP Solver. If klinear parameter (Linear Spring Constant) is set to 300 in wire object and then I'm writing inside sopsolver in point wrangle @klinear = 300; just for test, then my simulation looks different, less stabile (?). Why is that happening? This is the same value so it should be the same sim. I was trying to put sopsolver before and after the wire solver and there was the same situation.
  3. This operator allows you to run an OpenCL kernel as part of your SOP network. Depending on the GPU, some operators can be orders of magnitude faster than even VEX. In this case the OpenCL code is 144 times faster than VEX on GTX 970.
  4. raytrace

    Hello everybody, i'm finishing coding a small raytracer that run in sop using vex. one of those thing I always wanted to try to do myself. it store everything on points so no rasterization plane as the idea was to have all the rendering data accessible for later use as you would with any other attributes. it is some sort of an hybrid in the sense that it is correct enough to try to make things look good. it feature many BRDF shading models, photon mapping global illumination ( mathematically done the simple way but it work) and full recursive ray's tree splitting for reflections and refractions. Here a few videos showing some of the feature and a big part of them are already available for download as an OTL for the non commercial edition for everybody interested with the hope it can be helpful to anybody that never coded those things before like me, as I learned a lot during the way. here the videos: This one have been updated recently with lots of new clips showing improvements there and there And this one got th GI part of it with a little demo at the end. download link in the description area: Hope you enjoy, best alessandro
  5. Hey guys, working on a destruction peice and wanting to take the velocity from my charachter and put it into my bullet sim - So decided to try and use a sop geometry node to bring in the calculated velocity (from a trail and fluid source) - which is working perfect. But my sop force doesnt update each frame, its static - ive tried changing the expression from $T to $F and other things, not sure if its a limitation or if im doing something wrong? i will attatch a file but will be missing the geo but atleast you guys can see the setup Any help would be great! Thanks Destruction_v3_t2.hip
  6. Volume convolution on the GPU using OpenCL. For 27M voxels using 100 iterations, OpenCL is 650 times faster than C++ and 12525 times faster than VEX.
  7. Hello Guys, I am wondering if anyone can help me get my head around a little problem. I have a subdivided mesh being generated with a for each loop, similar to the Entagma setup, with an ends sop set to unroll. I would like to select a point on said mesh then have each point draw a line to its subsequent neighbour, repeating this processes until the whole mesh is formed...creating a kind of growth effect. I would also like to add some randomness to the speed of the connection on a per point basis. Now I have tried to achieve this a few different ways but I just can't seem to pull this off. Any help will be greatly appreciated. Thanks, Clive Growing_lines_between_points.hipnc
  8. Hi, can i use ch VEX function for accessing strings? If you open the attached file, you will notice that i am trying to move one point to a specific location..marked with another point (Demo scene ). I will get the location via opinputpath and point functions. First i will get the path via opinputpath, and then i use it in point method via ch function. Now, it seems that if i use ch function, i will get invalid location. When i use chs, i will get the correct one. Documentation/help says that there is version of ch function that returns string. What am i missing here? Cheers -kimmo ch_vs_chs.hipnc
  9. First post, and pretty new to Houdini (coming from C4d). What I'd like to do is have a flat grid of polygons that are acting as "pixels" whose color is driven by an underlying image sequence. That much I have been able to figure out using a grid of points, and then mapping a simple 1x1 square per point. I've been able to get a color per copy based on an image sequence as well, using a vopsop. What I'd like to do, is for each copy, read the luminance or color value, and be able to map an image to certain ranges of luminance. (example: black - nothing, gray - small circle, white - big circle) What i've tried so far always maps the pixel image to the whole grid, and not to the individual square. Any direction would be wonderful!! I could be heading in the complete wrong direction with this. I'll attach my hip, but without the image sequence it'll be hard to see what's going on so far. I'll upload a video as well showing the basics of what's happening so far. Pixel Grid.hipnc example.mp4
  10. Hi everyone, trying to figure out how to randomise the number of iterations of a pc open in a vop node, based on a per point random the goal is to make variation in the speed of the propagation. I join a simple file, if somebody can help me it would be really apreciated Thx by advance Cheers basic-propa.hip
  11. I just installed Houdini 15.5.683 for Ubuntu 16.04 and I gave a quick look to see how different was from windows version. The first issue that I encountered is with attribute-randomize sop, that gives me a strange error (VEX related). I tried the same setup in windows and everything works smooth! maybe is a ubuntu specific bug? there's someway to fix it, because this sop is essential to me. thanks in advance ps. I navigated inside the attribute randomize sop to find the actual line error.
  12. I am trying to scatter some points on a circle. But I want the points to be scattered more near the center and less towards the outer side. In the old Houdini Scatter I could do it by making my Circle Primitive type to "Polygon" and then uncheck "Divide Non- Convex Polygon" on the scatter node. However, in the new scatter node of Houdini 14 and 15, this option is not available. Here is what I am trying to achieve, this is with the old scatter node. This is what I am getting with the new scatter node. Please help.
  13. Hello to everyone! I'm fairly new to Houdini and to vfx at all and been struggling trying to do this by trial and error and searching in forums. Even though I have learned a lot by doing that, I think it's better to ask for someones help. I want to create some dust clouds (like a small dust storm) for a shot. Because the area that I'm trying to fill is big and my resources are limited, I thought it would be a good choice trying to achieve the effect using SOPs instead of a smoke simulation in DOPs. The setup related to this part of the effect is basically some boxes each modified by a Volume VOP to add some noise and animation by frame. I read that Billowy Smoke Shader can help you to get a more fluffy look at rendering. My first frame was great, but the next weren't as good because of the noise. The shader is supposed to use the rest field of your simulation to position it, but I'm in SOPs. Another user asked for something like this in the forum: He says: "just create a vector rest volume in the beginning that has the world coordinate of each voxel as its value. Be careful to do all the same advection operations on your rest volume as you do on your density volume". But I think a main difference is that they are working with shaped geometry and my whole dust storm is, well... a box. Until now my tests have been: 1.- Expose rest attribute with a wrangler before my volume vop and create a surface attribute named rest. 2.- Create it after the volume vop. 3.- Create the noisy volume, then convert it back to polygons, add a rest field and then again convert it to fog. And nothing worked. My questions are: 1.- Is there are way to use a rest field from SOP to shape noise in the billowy shader? If yes, what is it and how do you work it. 2-. Or would it be better to create a noisy volume, convert back to geometry, add pyoclastic noise and convert it back to volume? Thank you in advance. I would really appreciate your comments.
  14. Hi So I have an asset created at Obj level, and I want it to be avaible in the Sop context, so I tried by changing the the context from Obj to Sop (see attachment) and then matched the current definition and loaded the asset in a new scene, but it still appears in the obj context...any tips on how to sort this out?
  15. Hi, is there a way to reset object's rotation/translation procedurally in Point VOP? I think that i have found an answer for the translation part: subtract object's centroid from the point pos. But the rotation...argh - too much math that i don't understand Cheers -kimmo copy.hipnc
  16. Hi guys, here are the files I used for the last Vancouver Houdini User Group in case anyone wants to take a look. My presentation was about writing the Group SOP in VEX and trying to optimize it. I wrote everything in a wrangle, and it works great as a preset in a point/prim wrangle. I also made a Digital Asset, although it's not a VEX operator because I couldn't figure out how to make it work purely in VEX because I need to use the group bindings from the Wrangle and I'm not sure how to implement that in VEX. Anyways, the OTL is just the wrangle with the parameters promoted. In the presentation file you can take a look at the speed tests of the Group VEX vs the Group SOP. The difference in performance is pretty similar if you have a few points/prims, but once you go above 1 million the performance difference really starts to kick in. The Group VEX becomes exponentially faster than the Group SOP the more points you have. The difference can really be seen when you group by object and when you group by volume. I also made those 2 modes work with primitives. Here are the files in case anyone wants to take a look at the code. Feedback is greatly appreciated! group_vex_jeronimo_maggi.hipnc vhug_presentation_jeronimo_maggi.hipnc group_vex_jm.hdanc custom_group_sop.vfl
  17. fx

    Guys! Need your help! I stock.... Here is my issue. I have some particles that when impact with the surface (grid for example) create attr (marked as red for example). My task is grow this attribute by the time on surface in differnt directoins. I understand that effect can be achive by using SOP Solver, but can't understand for now how to do this. Explaning about how to make that happen will be highly appreciated! I attach hipnc file with my problem. Thank you advance guys! growing_attr_002.hipnc
  18. Sup guys, I've painted some stuff on an object and now I need to export this object to another software. I've projected UVs properly on it and now I'd like to export this data as a bitmap. I've found some info on sidefx forum saying this (on quote) but i'm quite new to shops and have no idea on what's going on there. Can anyone help me out with this, pls? My main doubts are: Should I do this in Shops? What is the Cf output? Use mantra -u option? wut? Thank you, /Alvaro
  19. Hey guys, I have a bunch of planes on a copy sop and I need all of them to be always "looking at" the camera. I found this topic at sidefx' forum showing how to make it at sop level (I know, at obj level it's quite easy ), but I couldn't make it work. This is what they did there: I actually don't know what to put at the "lookat_path". How can I put a path to another object, like a camera, in there? Thank's Alvaro
  20. I ran into a roadblock here inside of VEX. I'm trying to take the scale of these sphere and have them pulse. This is more for a visual aid for now as I want to take the spheres and plug them into a Shader's Emission so that the light pulses. Baby steps... However, in the meantime before I normalize them, I'm trying to get it so that each sphere kind of pulses at a random point in time. If you look, the scale of each is randomized, but I can't figure out how to randomly offset the pulsing so that it happens uniquely. I attached the file and an animated gif to help out! Excuse my messy VEX - I was going for as random as possible. scale_pulse.hiplc
  21. Hello How would I go about turning this into this? In order words, how would I rotate the hexagons so they fit properly? The hexagons in the first pick are copied into points that I put in the center of the second pic prims Alternatively, is it possible to control scale/rotate each prim individually in a normal geo? The effect I'm trying to achieve is creating a channel for each primitive in a CHOP network and then transforming them individually Thank you
  22. BulletSOP is implementation of Bullet library (bulletphysics.org) inside SideFx Houdini (sidefx.com). It's a plugin for creating incredibly large rigid body simulations on average PC. The Tool is very powerful, flexible and speed is very impressive as well as memory footprint. The plugin is free and without limits! So you can create truly stunning massive simulations. BulletSOP is compiled for Houdini production builds. It includes many example scenes (beginner -> professional) which are probably the best learning resources. Main features: - Bullet RBD Solver - Support for multiple Broadphases, Constraints Solvers - Loading data from previous frame - Geometry decomposition (Tetrahedra, Voxels) - Static/Animation body - Convex Hull - Compound Hull - Deform static Hull - Primitive Hulls - Constraints (auto-generating, spring, 6DoF) - Collisions Groups - Object Forces - Point Radius Forces - Delete Duplicity data - Instancing - Emitting system - Includes many example scenes for studying - Support for Windows(64bit), Linux(64bit) and OSX(64bit) Links: Houdini: www.sidefx.com LinkedIn: www.linkedin....Houdini-4796605 More author's videos: vimeo.com/user3251535 Create freely, simulate quickly and enjoy fully! Best wishes, Milan Suk Download BulletSOP v2.0.15 for Windows, Linux: http://bit.do/BulletSOP_v2_0_15
  23. Smoothing geometry on the GPU using OpenCL. In VEX it has to be done in 2 steps where the same thing can be achieved in OpenCL in one step using barriers [khronos.org]. For a 822K polygon model, it's over 500 times faster than VEX on GTX 970 for 1000 iterations, and over 600 times faster for 10K iterations. Timings are recorded separately as there seems to be some overhead when running them one after another. Special thanks to SESI.
  24. Hi there!! I have been using odforce for a while now, but this is my first post! I have just been playing with cloth tearing using the SOP Solver to calculate stress by analysing the distance between points and removing them based on a threshold. Just did it for fun! Any thoughts, comments or opinions would be great! Or maybe it will help someone... HIP file is attached. cheers G stressTest_GraemePhillips.hipnc
  25. Hi all, Consider you have a line made from 2 points. You subdivide the line to give you a new point in the middle, how can you add this new point to its own group? As a bonus, how could you group the resulting geo of any SOP?