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Found 85 results

  1. Hi everyone! I'm relatively new to Houdini, and I came across a tutorial which explained the bullet solver for H13. I am trying to recreate the effect that he got at 53:15, where primitives were deleted from the constraint network when a force over a certain threshold was applied. tutorial: As I understand, the SOP solver was changed in H14, and I therefore don't have the object merge node that he has. I downloaded the example HIP file and copied his node into my own project and managed to get it working, however I'd like to know how it actually works, rather than just copying and pasting! The data that the node is bringing in, is as follows: `stamps("..", "DATAPATH", chsop("relnode") + ":Relationships/" + chs(chsop("relnode") + "/relname") + "/" + chs(chsop("relnode") + "/relationship/dataname") + "/Geometry")` This isn't like anything I've come across so far in houdini - if anyone knows what this means, and could explain it I'd be very grateful! Best, Stephen
  2. N-body via SOP solver with OpenCL

    Here is it.:) nbody_opencl.hipnc
  3. I'm trying to drive a BlendShapes' SOP blend parameter using a point attribute, @fade. The @fade is a point attribute and have it's value animated. But the blend parameter doesn't appear to read this animated values and keep showing 0 instead. The question: the blend parameter doesn't work with point attributes? I tried VEX and Hscript forms (@fade and $FADE). The second crashes.
  4. I need an advice from you, guys! How the local attributes of PolyExpand2D SOP are to be used? I want to make a non-uniform offset with these inside scale attributes. But I do not know the workflow for this.
  5. Hey all, Sorry to add another Python cooking question (I've seen a lot, searching), but here goes. I have two subnets, a 'source' (from an .fbx) and a 'target'. The Objects in each correlate by name, and those in the source subnet are keyframe-animated. I'm driving the target Objects via: sourceMg = sourceNode.worldTransform() # beep boop, additional calculations go here targetNode.setWorldTransform(sourceMg) It works great, but once Houdini caches the frame the script is no longer (apparently) cooked, which makes sense--I pasted my code into a Python Script Object for convenient testing, which I suppose is not its intended use. If the HOM documentation is telling me what to do instead, however, I don't see it. There's the 'Python object' page, but I don't know that this is quite the same. In short: my script works as intended, but after the scene plays through once, Python stops moving the target nodes (I'm guessing because Houdini quits cooking it, since it's not doing anything Houdini expects it to do, like make geometry). Where does a script like this belong? I'm sure there's something embarrassingly obvious I'm missing--it's just a little extra confusing to me because I have to manipulate everything on the Object level. Thanks in advance for the help! If anything's unclear, lemme know
  6. Good old veins

    Hello. nice to meet you all, im new here. Have good old question about how to make veins grow animation. I usually do my work in c4d, but thought that it would be much easier in houdini, but its not atleast for me, im kinda stuck. What I want to make is a box filled with blood vesels, i need them to animate, how they fill the space (volume, i guess). One look i found nice was this I like how the brunch off into little ones and they are tapped at the ends(this i need most, and have most problems achieving). Im pretty clumsy around houdini as far as i have researched its possible to do with lsystems or point sop solver? (am i correct? ) If someone could guide me a little bit, would appreciate much. thank you.
  7. Just wanted to let everyone know that there is another new course on Pluralsight today. This time it's all about the solver SOP. Below is a bit of information. Hope you all enjoy! Exploring Houdini's SOP Solver by Kolt Wilson https://www.pluralsight.com/courses/houdini-exploring-sop-solver Course Description Houdini's SOP Solver is the industry standard procedural modeling tool. In this course, Exploring Houdini's SOP Solver, you'll learn how to create points, primitives, and vertices using vex. First, you'll explore some basic vector maths to allow you to have the knowledge and skills needed to create a wire growth solver. Next, you'll dive into using the Solver SOP and have the chance to learn several techniques via practical examples. Finally, you'll discover a setup that is built and has many applications. When you're finished with this course, you'll have developed several timeless, practical Houdini skills, and have the necessary knowledge to utilize those skills in practice. Software required: Houdini 16. About the Author Kolt Wilson is a designer and technical director freelancing in the northwest of the UK. Kolt began his career as a designer and 3D artist, where he focused on graphic and experiential design before making his way into commercials and film. Kolt has worked in the creative and motion/VFX industries for over 13 years and has been using Houdini, Cinema 4D, and Zbrush in recent years.
  8. 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
  9. 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.
  10. 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.
  11. SOPGI vex raytracer

    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
  12. SOP GEO - FIELD FORCE - BULLET

    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
  13. I have a RaySOP that is doing exactly what I want. It is shooting rays per point along a direction defined by point attribute 'rdir' and is returning the hitprims I'd expect. Hitprims are the green numbers in the images below, yellow lines are visualisation of attribute 'rdir' (raySop shown below) I want to be better about doing things with VEX so I tried doing the same thing with the same set of points, with the same 'rdir' attribute and same collision geo. I get wildly different results for my hitprims as shown below. heres the tiny bit of VEX I've got: vector p; vector hitprimuvw; vector dir = @rdir; int hitted; hitted = intersect(1, @P, dir, p, hitprimuvw); @hitprim = hitted; What am I missing?
  14. 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.
  15. 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
  16. 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
  17. 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
  18. 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
  19. Attribute randomize issue

    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.
  20. 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.
  21. 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.
  22. 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?
  23. 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
  24. Custom Group SOP in VEX

    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
  25. Growing attr on surface

    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
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